The only thing that you need to change is the game actually, because you have to be unique in order to catch somebody's attention to play on your gambling site, it needs to be interesting and entertaining at the same time, because that is how you are going to attract players, for them not to easily leave your site after they played your games.

and of course you have to lower the house edge, because that is the other thing that everyone is looking when they are playing on the gambling sites, the lower the house edge, the higher the chance that they could win, in short, you have to make a gambling site that is fair to them.