Well said mate, all tips and advice you have been mentioned are really helpful to them but the problem is how to execute to themselves.
Yes, to execute them must depend on the gambler. Few gamblers may think they are common sense and not really necessary things. For typical gamblers like this, we cannot help much. But at least, we have already reminded them with those suggestions. 
Let me add something that based on my opinion.
Thank you so much for these additional suggestions. I will put them directly on the OP. I'm waiting for your other feedback on my other threads. Very nice to see your contribution to support the topic. - Don't gamble if you are depressed, stress or something has negative emotion in your self.
- Always think gambling is a form of entertainment, not a way of making money
- Always set a time limit of how long your session in gambling
- Decide to stop when you are in a win-win situation, the more time you gamble, a big chance to lose.