Not sure when I had my first depositing player, but it took me a year to become profitable and then I plowed most profits back into the site and I still do that. (been 8 years now)
When you have a new site, don’t try to cover an entire subject but focus on something you know about, or can and would like to learn about.
In other words, don’t try to cover all of online gambling but focus on a specific aspect of it. You can always expand later, or start additional sites on other topics, depending on what business model you choose.
Write lots of good quality content, things that will help players play smarter.
Make sure you pick good properties to promote – properties that treat both players and affiliates well.
There is plenty of room for everyone in this industry. When I got started, everyone told me I was too late and there were too many good websites already. People are still being told that, and it is as wrong now as it was then.