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?

Very true. Especially budgeting.
When you don't budget on what to spend, you'll end up spending everything with hope that the great wins are not afar, when, in reality, they might not be in sight that day.
Another will be, have metrics for gambling. Just like trading, if you have a setup, you'll always wait for your setup to activate any trade rather than jumping into the market.
Same goes for gambling and betting, ensure to have your metrics of gambling before you adventure into it. Lets say you want to bet on a team and that team has been unpredictable in that season, just stay out of it and avoid the risk.
Setting a budget is quite okay because when you make budget not only in gambling, it makes you stick to things that are within your budget and you have to be determined not to go against your principles no matter how tempting it is because I know there are times when one is in need of money so bad that immediately you lose a bet you might want to try more with the hope that you might win on several attempts.
And again avoid betting on too many events in one bet instead you can split the bet as there might be chances of succeeding in outcome of one of the event because the risk would be lesser compared to when you make so much accumulation