controlling your emotions in gambling is just the start towards a better result in your games but not the end game.
if you want a better series of results you need a good strategy and in many games like sports betting or poker you need a lot of experience to win and controlling emotions comes after this step.
It is easy to say "control your emotions".. As you wrote, it is possible only when you have very big experience, but the amount of bid can distract every player
For me, the most important to control the emotions is a strategy of game, which should be prepared before the game starts.
Yes it is easy to say that word but applying it to ourselves is where we are having problems, let's admit it that everyone is also facing this problem.
But once you are able to have a lot of experience with gambling, you can just simply learn it plain alone. And for those gamblers, no doubt about that most of us runs for the profit and that's why many are asking about safe method, the answer is none.
You may now can think so fresh but you will be underpressure in the game and react spontaneously , there will be no control here.
So yeaa it is easy said than done, never safe to gambling in any way.