With the increased proliferation of online guitar and musical equipment stores, as well as the lower prices and greater selection that these stores generally offer, most people are now turning to the internet to help them make their guitar purchases. Shopping online is simpler and more convenient than shopping in a store and, since all major guitar manufacturers have good websites, product information and specs are more easily accessible online than they are simply by asking a salesperson in a store.
The only downside to shopping online is pretty easy to figure out: there's no physical contact with the instrument. Think about it, when you're shopping for a new car, you can get in, look around and take it for a test drive. With shopping for a guitar online, that's not generally possible. This means that you have to educate yourself a bit more about what you're trying to purchase before you actually take the plunge.
Not all guitars are created equal. Although, with the improvement in manufacturing processes and technologies, purchasing a "bad" guitar for more than $250 is difficult to do these days. Talk to your fellow musicians, either in person or on an online community or "blog" and see what different people have to say about the instruments they've played. Many online stores allow their users to rate their products so, along with the general information about the guitar, you can also find out what people who bought the guitar thought of it, and why.
Research what your favorite guitarists play. Not only in terms of brands, but in the configuration of the guitar itself: was that fantastic solo played with a single-coil or a humbucking pickup; why do country guitarists typically use Telecaster-style guitars? In answering these questions, you will better educate yourself about what type of guitar you are most interested in. Don't forget, if you buy something online that you aren't satisfied with, almost all online stores have a 30 to 45 day no fault return policy.
If you don't know where to begin shopping, check out http://www.guitar-4u.com. They have the best selections from all the major manufacturers, as well as detailed information about the manufacturers as well as all the products they offer. Happy hunting!