Originally Posted by NLBwell
You are only as good as your second serve.
I was going to say that but I guess I was too late.
Like the others above me said, your serve can't be the best for your level if you are constantly double faulting. Do not overestimate your serve, a fast serve does not necessarily equal a good serve. I'm assuming you aren't good at creating spin on your serve with the way you described it. Work on that, by adding spin you can decrease double faults and add variety, then your serve will truly be a weapon.
BTW Moya isn't a good analogy, when you think of him you imagine a typical clay court player (gets a lot of balls back, retriever, consistent). Correct me if I'm wrong, but he seems to be a 1-dimensional player. Efficient, but one dimensional. You haven't really described your game but a tactic you can use is to just mix it up, keep hitting him different kinds of shots. This can help neutralize his forehand and expose his backhand's technical flaws. Remember to build the point to maximize your strength (whatever it is) and apply it to their weakness (his backhand).