I use martingale strategy it is easy but high risk.. need big bankroll

I don't know what is the best strategy..
You need a big bankroll for martingale but you also need big limits in whatever game you are playing in your favorite casino, but I think martingale sucks as a strategy because you only need a few losses in a row to never see your money again.
Regardless how much bankroll you have, I do not recommend martingale system. It will eat your entire bankroll when you have a cold streak. It's not advisable for a gambler who loves to play and last in the game. Just be conservative and use flat betting.
Not only martingale method but no methods will work, if anyone gambles to make money from it because only luck can bring money from these games. You can be lucky for some time but if you play every day then you will lose more than you gain. So just gamble only for entertainment purpose, and you will surely make some money if your lucky on any day.