This is a very hard question, but i think you must set you 2 limits.
1. The time limit. You set you a limit of 1 hour and you dont play not more than this 1 hour.
2. The winnings. You must set a winnings limit for example of 200 Dollar. After you won this 200 Dollar you dont play anymore this day.
Because without these 2 points it will be hard to stop imo.
I think time limit is a bad idea but setting a goal when you reach it, stop the gambling right away. The problem is second thought, which makes people think they can win more so just make a firm mind and withdraw all you have once goal is reached, dont think much.
The ideas are good, but I don't know how many gamblers will follow these methods. Because once we start to play gambling in our mind nothing will come to our only goal is to win our bet. So I this process we will forget everything what we planned before start to play. If you can control your emotions, then only you can able to follow these methods otherwise making plans is no use.