If you haven't yet, find a good gundog book and read it.I would highly recommendDelmar Smith/Bill Tarrant's book to get a handle on dog training. It will help in finding the right trainer. Alot of trainers methods
are based on it.

Find and join a club. NSTRA,AFTCA, or any club of that style - mainly, field, upland birds. NAVDIA style are okay but mainly geared towards versatiles. The NSTRA club in my area usually gives free training clinics every year.