I have found that if I gamble, I need to set rules and stick to them. For example, I have only certain games that I will play and I limit how much I'm allowed to bet. Also, after a predetermined amount of gain, I have to stop and after a predetermined amount of loss I have to stop. It helps to have some rules to follow.
Good for you if you can manage to follow your rules, thet are actually great. I'd add only one more maybe: limit how much time you spend on gambling because apart from moey it is also a waste of time.