This is just the basics, but anyone should be aware of it:
Budget: set it BEFORE you start gambling and stick to it.
Have a break from time to time, it is important to let your brain stop and consider.
Avoid drugs / drink as much as possible, they will make you loose some control innevitably.
Seek help if you feel you are no longer in control. Make a phone call to a friend or go out and speak with someone.
Anything else anyone can think of? Like... read this post before gambling?
Mindfulness, Self-awareness, Self-control, and Discipline is the key. These bits of pieces of advice do really work. It is proven.
But only if put into action.
You can set a budget before you start gambling. 5% or 10% of your capital. But how disciplined can you stick with it.
Take a break when you get to win, and don't give back your profits. How can you control yourself?
How mindful are you to avoid drugs and alcoholic drinks? How do you seek help when needed?
These questions are hard to swallow and to answer, but it's the key. You don't need techniques, you need to master yourself. It may seem like, there is no related to gamble in here, but gambling is a hard psychological game. You lose money, you may also lose yourself. So take care of yourself as you take care of your accounts.