The best way to promote your casino site is to use both free and paid advertising.
Here is a small list of the things that you can do to bring as much traffic to your site as possible.
Email marketing on other people's list.
Post your comments on other blogs.
These are just a few.
I would focus more on paid advertising because it has the most potential to get your lots of traffic each and every day.
Plus, you will also want to create your own affiliate program where your affiliates can earn a percentage of your sales.
Doing this will increase your income and get you a lot of free traffic from your affiliates.