You just have to stick to legal, regulated online casino sites such as BetMGM, Caesars Palace Online Casino, FanDuel, Betway, bet365 and BetRivers. They offer great casino game ranges and they will pay out quickly and without any issues if you win.
Every casino game has odds more favorable to the house than the player. This is true for both online and brick-and-mortar casinos. So this guide isn't about how much you will win, this is about how much you can win. And you can win a lot of money at online casinos.