Learning to fly cast can be a difficult experience. I know of at least 3 anglers that spent thousands of dollars on fly equipment only to have it sitting in the back of their garage after a failed learning experience. Apart from buying their gear off them the only help I could give them was get on the Internet watch some videos about fly casting technique and start again (for the record none of them listened).
I must admit I learn best by watching other people, which makes me pretty lucky I guess. With the Internet I can watch how to tie a knot, cast a fly, bait a hook etc. and this makes learning new things very easy.
The following is the video I used to help me learn the basic fly casting technique. Remember that youtube has hundreds of videos like this so take a look through, have a practice and find a technique that works for you.