Your guitar's action, or how high the strings sit over the frets, determines many factors in your playing. A high action can give a more powerful tone, but is often difficult to play; low action, on the other hand, is easy to play, but can lead to fret buzz and bring out the flaws in a loose technique. With a Floyd Rose-equipped guitar, in particular, low action can be problematic by interfering with the tremolo's movement. Setting the action on your guitar is largely personal preference, but remember that there are some heights that work better than others.
Determine if you need to raise or lower your action. Raise it if you are having problems with fret buzz or dead notes, and lower it if you want easier playability. Test your action by pressing down the high E string at the first and 20-second frets (use a capo for the first fret). Hold a ruler at the 12th fret and measure how far the string sits above the fret. There should be about 2 mm between the two; any less and you will likely have string buzz problems if you lower your action. If the gap is wider, you could probably make your guitar easier to play with a lower string height.
Raise or lower your tremolo to adjust the string height. Use an Allen wrench to turn the pivot screw that connects the tremolo to the guitar body. Turn counterclockwise to lower your action, clockwise to raise it. Turn both screws to equal heights, and don't allow the tremolo baseplate to angle too sharply while you adjust one screw.
Test your action by playing every note on both the high and low strings. If you have significant buzz on one or more frets, you'll need to raise your string height. If fretting notes is difficult, lower the action. If one string buzzes but another doesn't, you can offset the angle of the tremolo to raise the problematic string. Just be sure to keep the angle shallow--you don't want to impede the unit's performance.
Repeat Steps 2 and 3 until your action is comfortable but you don't have significant string buzzing or difficulty playing.
If you cannot get the strings comfortably low without fret buzz, consider taking your guitar to a repair shop. The neck may be poorly angled and may need adjustment.