If you want to do it for a bunch of $ then hire a coach.
If you want it on the cheap. Begin to hit the clays course on a regular basis and see who is hitting them. Once the regulars see you around for a while they will usually help you out and give advice. Never be afraid to ask. I would be hesitant to help someone (only been doing this for about 3 years and still learning) but if they asked I might be able to make suggestions on how to stand where to hold, with out causing too much damage.
I started helping out at my club when I started shooting clays. It is all volunteer, I would stay around and try and help clean up, put machines away etc. The good shooters tend to notice those types of things and began to give me tips on improving stance, hold points etc. A couple of the guys who shoot there all the time shoot skeet on a competition level began to invite me to to shoot with them during their practice sessions etc. Another guy shoots competition trap and another used to be a top sporting clays shooter. I learned a ton, it is like private lessons, and gained a bunch of friends in the process.