Thank you everyone for your answers! Seems like signature campaigns will be my first move.
Not a casino owner here, nor was I ever involved with any casino team.
But whoever having a good time here has a long running signature campaign and they are having great time as I can see they are here for long time.
If you are looking for a great signature campaign manager, look at here-
https://bitcointalk.org/index.php?topic=4412712.0But before going into having sig campaign, much better if most are already in place in your casino. Maybe, as a start, run for bug bounty program. At least, with this bounty program, users will help you find out the possible vulnerabilities of the site so you can address it before fully launching the site. In this phase also, users know that you still need to resolve those possible bugs inside the casino. Also, once launched, expect that you will receive criticisms from the community. Take those as pointers that you can improve the site.