well if i were you id start off on a new bike.....
dirt jumping - build some small ramps and jump em then make em biggger and work on that
street - find a ledge and wax it up real good and start grinding and learn manuals
i cant help you on vert
but you can try flatland too www.danscomp.com www.flatlandfuel.com
like they said, build jumps, make them bigger the better you get.. find a half pipe and just carve the walls over and over until you get better and better. and for street, man, just have a ball. Practice bunny hops and do stair-gaps and try to hit ledges, do stuff you cant do yet, and just have a great time.