I think you need to control yourself in gambling and being discipline about your strategy, how you play and how well you calculated the winning odds could make your strategy works better, luck can't be rely on in gambling, you need to build strategy to win based on your experience, and strategy is only to help you prevent losing money not to add your winning percentage
It is very difficult to developed gambling strategies and even if one has a good strategy I will agree with you that " we should be discipline about our strategy", since we can not win all the time? The best way to handle things is to reduce your risk and gamble with carefulness!
Gambling is won by being disciplined and manage your time and money properly. If you know how to manage your money in gambling, you will be in a position to win from gambling. Although success is difficult to achieve in gambling but by following some strict rules, we can avoid big losses in gambling.