I hate to answer before the man lol, but all it really takes is what u already mentioned, practice.... the more u make beats the better youll be and the more accurate and creative your drums will come out.... be creative, try new things.. listen to the drums in different songs, understand their grooves and study where they hit.. study their velocities and find out what works for you... test your creativity with your equipment.. if you use a step sequencer itl be alot easier to really break down the math of exactly when the drums hit and the time signatures...