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?

You've highlighted very notable and helpful points, but on thing about addiction is that, at that point nothing else matters other than what you're addicted to, when a gamblris addicted, even when he realizes he needs help, and he's given some tips that'd help him fight the addiction, sticking to those tips is another battle, maybe he can try to do it for he first and second day, but that's it. So here are some points I feel would also be helpful to help fight the addiction faster.
1.
AVOID BEING ALONEYou're likely to thing about doing things you're trying to get away from when you're alone or lonely, s try always being around people and friends ( who don't encourage gambling) they say you're likely to be like who you hang around with, so always handlg around people and avoid being alone at all time, except you're alone busy with something.
2.
LOOK FOR A NEW HOBBYYou got addicted to gambling because you got too attached and used to it, so changing your hobby and finding something else tht excites you would really help you in getting rid of your addiction quickly.
3.
GET A TRUSTED PERSON TO MANAGE YOUR FUNDSIf you're addicted to gambling, another way that can help you fight the addiction is looking for someoneyou trust to help you manage your funds, it could be your colleague at work, your secretary, your spouse or anyone you trust. That way you don't have easy access to your funds and can't gamble at will.
These tips could also be helpful