Having self-control is a big deal, at least you have an idea what are the consequences of too much excessive playing in gambling. People who have a lot of money are the one who enjoy gambling because they can freely bet until when they like because they know there's good money circulation on their part, but to those who have a limited amount of course there's a limited bets only that every drop of the money you have is how much you get afraid to lose. I don't even have luck with the last drop money most of the time I let it go and make one last bet but in terms of a comeback game with that money I haven't yet.
Self-control is the main priority in gambling activities to control emotions to avoid the potential for higher losses, self-control is not always tied to the level of budget limits that gamblers have because it is useless for some gamblers to have a lot of money but they experience high losses due to not gambling responsibly, even though Gambling is claimed to be just a game based on luck but the fact is that some gamblers gamble using good strategy and good self-control, they will not experience high losses and they have the skills to win on certain bets, especially on soccer bets and also slots. So don't force yourself to gamble using your last drop of money if you are not sure of winning, but use the money to make a deposit for the next gambling so that you gamble with fresh self-control and are not disturbed by thoughts of previous gambling losses.
We all know these things so well, funny enough even the people that goes extreme with their gambling activities are all aware of the importance of gambling responsibly. So like you rightly said, it isn't just enough to know it, but to practice that self control is the key thing and the most difficult thing when the need arises as its easier said than done. The only effective way to control yourself its not to fund the account with more money than you're prepared to expend for a session.
Another thing is that these gambling newbies don't really take these things seriously until they've been disadvantaged somehow, we all know how we started and personally I wasn't cautious of my gambling involvement until I've hit a big rock financially, then my mind was open to reality. That's the same with most newbies, your advise seems like a disturbance to their gambling exploration until they've met a hurdle and decide to face reality.