I think make a unique gambling game or casino that different in any gambling casino here.. so that you can get more people to gamble in your site if you make a newly game that you can gambel and entertainment for a long time ..
Well if you want to make some gambling sites which are unique there are some requirements also, very first is your capital, it must be in a range of 1000 btc together the website and many aspects that completed as a gambling site. But as OP maybe i can suggest that you have to hire some devs that is expert with cryptocurrency and make some alts that will contribute to crypto world.
The capital is really the important thing as that would make to realize our goal to build a gambling site, and we are talking here of serious money because there are a lot of factors that needs to consider in starting an online gambling sites, the promotion itself will already require you to spend a decent amount of money.