There is no way to gamble in a safe way because the chances of you winning are still going to be the same no mater what you try to do.
With most of these gambling games luck is required in order to win and that is a fact.
The chances of winning will be the same no matter what we do? How about if we set the multiplier at 1.00x and then 9999.99x? Those two have the same chances of winning? There's a lot of factors that would affect your chances of winning.
In dice games, by setting the multiplier in a really low one. In sports betting, by doing tons of research about teams and see who's got the upperhand. However, there are still cases when you expect a sure win but then that small percentage of you losing miraculously wins over the percentage of you winning.