study stuff you like intensively.
use loops and see how they work. then try to re-do those loops.
the *.rex format comes in very handy for this.
get your hands on some percussion/beat midi files and use your own sounds with them.
run a randomize function over an array of percussion and pick the loops that sound usable.
practise and don't give up - that makes all the difference.

persistence is key!

any examples of what you are trying to achieve, tracks, artists?