There is a lot of ways to advertise it but I think social media is not a good way to advertise it as gambling sites are not allowed on it but there are other things like sponsoring a team, handing simple competitions in the forum or running a signature campaign. It will be more effective if you hire a good campaign manager and marketing team.
It like op want to make an advertisement here. He knows that he can always use social media to advertise his casino but I think he is more concentrated on this forum cause there are more users and gamblers here since his intentions is to launch a crypto casino. Signature or bounty campaign is a good one to use and adverse your casino. There are many users here that are campaign managers that can organise users which can run the signatures or bounty.