We all want a solid community and reputation of a casino as that really makes a gambler confident and worryfree whenever we gamble on them plus having a good and very responsive support.
For that reputation and solid community to start with, the gambling site should think of those primary good things and features that will attract those users. Once those good features will be introduced with no problem, that would be the start of building a good community.
Aside from that, while the community is growing, the gambling site should have a dedicated team to always answer questions and queries as quickly as possible and don't leave their users hanging or idle for several tickets waiting to be answered.
A special reward for users that can find some bugs can also be considered at the start of the gambling site's operation.