If you have a hunting partner, try to have him set up behind you about 30 yards and call from there. That way you will be between him and the birds so when the birds are hanging up from his calls you will be within gun range of them. It is very imperative that you are well concealed and that you do not move at all. Their eyes are amazing and they are very paranoid birds, it doesn't take much to spook them. Also, don't over-call because the tom wants the hen to come to him. If you call sparingly, he will get anxious and come looking for you. Good luck!
-Chris