You may notice that most discs are marked with a set of four numbers. These are (mostly) industry-wide standards for describing flight patterns, and having a basic understanding of them can help you know what type of disc you're looking at without having to go out and throw it.
The first number is speed, which is largely self-explanatory. Discs with higher numbers are designed to travel further and faster, while discs with lower numbers will fly slower over shorter distances. The tradeoff is usually that it is harder to throw a disc with higher speed accurately.
Next is glide, which describes the ability of a disc to remain in the air for a long period of time. A high glide disc will capture the air beneath it as it moves, giving it a longer time to stay in the air, but it also means it is more sensitive to gusts of wind.
Bend and fade refer to the nature of the flight path of the disc, and are slightly more subtle. As the disc leaves your hand, it will naturally turn to the right, but less turn will cause it to bend more strongly, and more turn will keep it more stable. The fade, on the other hand, tells how much the disc will turn to the left after completing its initial bank. Keep in mind that this is for right-handed players throwing backhands, so if you're a lefty, the turn is how much it turns to the left initially, and the fade is how much it turns to the right.