Just to add on to what the rest had prescribed previously:
- books are very encouraged. buy a couple, and work through them. buy somemore. you'll find yourself improving significantly.
- play along CDs. some books come with them (like the grading course books)
- find and form a jazz band. work through standards, experiment a little. maybe take a song that is not often covered and try it out.
- get lessons from a teacher. different individuals have different perspectives on what they've learnt.
- listen to as much music as you can. Take the time and go through an artiste's material, especially the seminal ones: Miles Davis, Art Blakey, Dave Brubeck and so on. For example, you can hear differences in style and approach to jazz drumming from the different drummers miles davis used over the years:
birth of the cool (max roach, kenny clarke)
kind of blue, sketches of spain (jimmy cobb)
live at montreux festival '63, seven steps to heaven etc. (tony williams)
bitches brew (cobham, lenny white, jack dejohnette)
maybe you'll find yourself having an opinion and liking a particular drummer's take more so than others.
- go down to local jazz places and listen to them as much (JSB, regent hotel, barfly etc.)
if you have questions, i'm sure the drummers (boon gee, tama, audrey) would be happy to answer. ask intelligently and be aware they need some breather and rest from playing of course!
cheers