Best secret is to prevent it from happening in the first place. Some of the man-fighting can have a genetic component but a larger part with respect to games comes with your approach to handling, especially during the early stages. Once man-fighting realized in a bird, it takes a fair amount of investment to back him out. My approach involves a lot of time around bird so stress reduced through acclimation and at some point he needs to try himself against you without being able to see fruits to his labor. In other words he needs to be able to relax and realize he can not drive you off or whip you even when he can put it to you. In the process he must also not see aggression coming from you. For me. this problem with games is very infrequent although with non-games where genetics more important it is pretty common. Your husbandry technique needs re-evaluation if man-fighting occurs frequently in birds you raise.