Re: difficulty with serve
kind of hard to give advice w/o seeing, but here are some suggestions.
the main things to work on:
-a consistent toss(not too far out in front or behind)
-pronation of the arm
-using legs to push from the ground(more upward than foward)
alot of the serve is timing( of the toss,knee bend, push and swing). just hit alot of serves and try and find a timing that works for you. Hope this helps.