I think that we need to gain experience with different bets, different situations with losses and big wins, after which we will not be too interested and it will not cause us too much emotion, and when emotions are at a low level, then we can concentrate on more reasonable and balanced decisions. In addition, some can be helped by various things like watching how others win or lose huge amounts and imagining what would happen to us if we were in his place. Although it may not help some very much.
Experiencing different kind of bets and situations will help us improve to become better gamblers.
And it's not about being a better and winnable gambler but being responsible and how to respond in hard situations that we cannot control ourselves anymore.
Learning from the others is one way but it's true that it might not help us a lot when we're confident we are in control until we're no longer.