Few tools of modern technology have become as prevalent as the cell phone, which allows you to be in touch (almost) all the time, (almost) anywhere. And you can do more than just talk–today’s phones let you send and receive email and text messages, surf the Web, and play music and videos. Sifting through the sea of service plans and handsets can be difficult, but we’ll walk you through what you need to know to get the phone and service plan that are right for you.

If you don’t have to own the latest and greatest smartphone, there’s no time like the present to buy a new one. From the newest iPhone to an Android superphone to a business-friendly Windows Phone, you can find the right phone for you. Before you hit the stores, however, do a bit of research and read our guide so that you’ll know exactly what to look for.

Features to Consider: What should you look for when you’re shopping for a new phone?

Picking the Right Plan and Choosing the Right Carrier: Deciding on a plan and carrier is a daunting process, but we have some useful tips.

Shopping Tips: Arm yourself with knowledge before checking stores.

Features to Consider

When you’re shopping for a phone, you can do some simple hands-on tests in the store to make sure that the handset has everything you need.

Call quality: What good is a phone if it can’t make calls? Some of the most simple, bare-bones “feature” phones offer the best call quality–and on the flip side, some fancy smartphones offer dismal calling. When evaluating phones, be sure to make a few test calls. In PCWorld’s hands-on tests, we generally make some calls in a quiet room and several calls in a noisy environment. You might not be able to replicate such tests indoors, but try your best. Take note of static, tinny voices, or any interference. Ask the person on the other end of the line if they can hear a disruptive amount of background noise.

Design: Your choices range from phones with large touchscreens to slider-style handsets with full-QWERTY keyboards. Whichever type of phone you select, check its ergonomics. Is it comfortable to hold against your ear, and can you hear callers without constant adjustment? Can you use the phone with one hand? Consider hands-free use: Can you comfortably hold the phone to your ear by scrunching your neck and shoulder? Can it fit comfortably in your pocket or bag? You also want to make sure the phone is durable enough to handle some roughing up. A solidly built phone should be able to withstand getting banged around in a handbag or pocket, as well as a bit of moisture and a short-range drop. You should think about investing in a case or display protector, as well–especially if you’re accident-prone.

Operating system: If you’re looking to do more than make calls and send text messages with your phone, consider the platform on which it runs. The mobile operating system you choose will greatly affect the capabilities of your phone. The most popular platforms are Google’sAndroid (found on multiple devices), iOS (found only on iPhone models), BlackBerry OS (found on BlackBerrys of various designs), and Microsoft’s Windows Phone 7. Each has its advantages and disadvantages; you should definitely familiarize yourself with all of the platforms before settling on one.

Display: If you intend do a lot of Web browsing or movie streaming, make sure that the screen is up to snuff. Is it big enough for you to take full advantage of the phone’s features? If you’re going to surf the Web or edit office documents on your phone, a screen that measures less than 3 inches diagonally will feel cramped.

Consider the screen’s resolution: The higher the resolution, the better the screen will look–an important factor if you plan to use your phone to watch videos or view photos.

AMOLED displays perform well in sunlight, but many people think they make colors look oversaturated. qHD displays (whose resolution is one-quarter of a full-HD 1080p frame and three-quarters of a 720p frame) generally look the best in video playback and games.

Being able to take control of the screen’s contrast and backlight settings can also be important, as phones have noticeable differences in their default display settings. If your phone allows you to adjust contrast and brightness, you can make text and graphics more easily viewable in well-lit places, and you can also save battery life in a pinch.

4G support and availability: After a lot of buzz, the next generation of wireless networks, 4G, has arrived. The two main technologies are WiMax and Long Term Evolution. Though Sprint’s network currently uses WiMax, the carrier will begin deployment of an LTE network at the end of 2011 and will release LTE devices in mid-2012. 4G’s faster download speeds significantly improve streaming video, and allow features such as videoconferencing and network gaming.

If you decide to buy a 4G phone, first confirm that your area has coverage. Verizon currently offers 4G coverage in 175 U.S. cities (check the carrier’s coverage map). Sprint has a complete coverage map of its WiMax network, too. AT&T has launched 4G LTE in 15 cities, and plans to reach 70 million people by the end of 2011.

Currently AT&T and T-Mobile are promoting their HSPA+ networks–which essentially use a more advanced version of 3G protocols–as being capable of achieving 4G-like speeds. If you’re looking into buying a 4G phone on AT&T, confirm whether it supports an LTE network or an HSPA+ network. Generally a 4G LTE phone will have faster data speeds, but it may also have limited coverage. We have seen “4G-like” speeds on HSPA+ phones.

Cameras: If you intend to take a lot of photos with your phone, you’ll definitely want to pay attention to the camera specs. For mid- to high-level smartphones, 5 megapixels is now pretty much the standard. Some phones ship with 8- or 12-megapixel cameras, but a higher megapixel count doesn’t necessarily mean a better camera. Verify that the phone camera you’re interested in has a flash–dual-LED or Xenon flashes work the best–or else any pictures you attempt to take indoors or at night will come out looking like blurry messes. Try to take a few pictures in the store to get a good idea of the camera’s photo quality.

Most cell phone cameras also have video-capture capabilities; some high-end phones can even capture high-definition 1080p video. If video is your thing, make sure that the OS provides an easy way to upload your videos to services such as Facebook or YouTube.

Many modern smartphones have front-facing cameras. These are mostly good for making video calls; but some camera apps, such as photo-booth apps, use the front-facing camera too.

Processor speed: We’ve heard a lot of buzz about phones that use dual-core processors, but such power is really not necessary for the average user. Unless you’re doing a lot of app multitasking or playing games with 3D graphics, you’ll probably be fine with a 1GHz processor. Aside from the processor speed, other factors–such as the version of software your phone is running (Android 2.3 is faster than Android 2.2, for instance) and the speed of your network–contribute to speedy, fluid phone performance.

Battery life: There’s no easy way to predict how long a phone’s battery will last. In our PCWorld Labs tests and our hands-on evaluations, we’ve found that 4G phones have a shorter battery life than 3G phones do. Ultimately, however, it depends on how much you use your phone. You can download task killers or battery-management apps that may alleviate some of the drainage. You can also buy a case with a built-in wireless charger, or carry around an extra battery for your phone. For a complete guide to extending your phone’s battery life, check out our “How to Boost Your Smartphone Battery Life” article package.

Picking the Right Plan

While shopping for a new plan, be completely realistic about how you will use your phone. The national phone plans that the major carriers offer will let you send and receive calls anywhere in the United States (and even in parts of Canada) at no extra charge. You may be able to sign up for a local or regional plan that limits the areas where you can originate a call and still pull from your monthly pool of minutes; this option might be worth considering if you use your phone for local calls exclusively. If you have a world phone and plan to use it in other countries, choose service with international roaming.

As you’re selecting a plan, it’s best to overestimate the number of minutes you’ll be using for every sent and received call. Because one carrier’s definition of off-peak may be different from another’s, ask the carrier to specify the times for its peak, off-peak, and weekend hours.

You should also take into account your data usage (for email, video, connected apps, and Web browsing) when picking your cell phone plan. Most carriers bundle voice and data plans together. Customers on AT&T, T-Mobile, and Verizon are capped at how much data they can use before extra charges kick in. Sprint is the last U.S. wireless network to offer new customers an unlimited data plan.

Choosing the Right Carrier

Tired of your current carrier, or shopping for your first smartphone ever? Choosing a carrier is a daunting task. Most likely you’ve heard of the Big Four: AT&T, Sprint, T-Mobile, and Verizon. You’ll also encounter smaller, regional carriers such as Cellular One and U.S. Cellular, as well as prepaid carriers like Boost Mobile, Cricket Wireless, and MetroPCS.

Before you start examining plans, find out whether you can get solid coverage in your city, town, or area. Ask your neighbors about the carrier they use, and whether they have reliable service. If you don’t have good coverage in your home, you’ll be in for a frustrating two years. You should also check the coverage for any other areas where you spend a lot of time, such as your office or a friend’s or relative’s house.

Customer service is another factor to consider. Every year, PCWorld polls readers on carrier service and support. In last year’s Reliability and Service survey, T-Mobile excelled in phone support. According to the survey, T-Mobile’s average hold time was 4.6 minutes–significantly lower than the others, which had times ranging from 5.2 minutes (AT&T) to 6.1 minutes (Verizon).

And 84 percent of T-Mobile customers reported that they were satisfied with the voice-call reliability of the carrier’s network, second only to Verizon’s 86.7 percent.

If you’re not into the idea of signing up for a two-year contract with a carrier, try a prepaid plan. These days you can find full-featured Android or BlackBerry smartphones with prepaid plans that offer unlimited minutes, text messages, and data, plans that cost less than half of what the equivalent ones would cost with AT&T or Verizon. For more information, check out our comparison of prepaid plans, as well as some reviews of smartphones available for a prepaid plan.

Shopping Tips

You can purchase a new phone directly from a carrier store; if you’re not sure what to buy, however, we recommend going to a third-party retailer. Best Buy, RadioShack, Target, and even Walmart sell phones, as well as carrier plans. A big advantage of buying a phone or a tablet from a third-party seller is that you have dozens of phones from multiple carriers at your disposal. If your contract is up and you’re trying to choose between the iPhone 4 (AT&T) and the T-Mobile MyTouch 4G, for instance, you can compare the two phones side by side in the store. You can’t do the same at a carrier store, because those phones are on different networks.

If you’re considering buying a phone as a gift, definitely consult with the recipient before you go shopping–and although it will ruin the surprise, you’ll probably want to bring them along on your shopping trip. We recommend getting as much hands-on time as possible with multiple phones before settling on one.

When dealing with store representatives, ask them to be as straightforward as possible. Tell them exactly what you’re looking for, and what kind of phone or plan will fit your requirements. If you’re completely unsure, ask the representatives what phone they use, or which phones impressed them this year. Don’t let them jump into a sales spiel, or else you’ll end up spending way too much time in the store. And remember, they’re human beings too, and they’re working during the holiday rush–be courteous, and you’ll receive the same treatment in return.