It is a good idea to regularly visit
to see if the T&Cs of the casinos you choose are ok for affiliates. And they sometimes change for the better or the worse, so it's good to keep up or you might find yourself failing and you don't know why. Affiliates get cheated at least as much as players, and likely more since there is no way to accurately prove the statistics you are provided with are correct.
That site also currently is running a free apprentice program, but I don't know if there are still openings. If there are, I strongly recommend it, you will receive all kinds of help and guidance.
I agree with everyone else - be unique. You can do it still. Sit down and make a list of things you would have liked to have at your fingertips when you first started playing. It helps a LOT if you are a player yourself, most of the bigger affiliates are players.
When I got into this business some 8 years ago, everyone told me that it was too late to break into it, and that my site was not going to work.
Nothing changed, people still tell newcomers the same thing. If people tell you your site won't work because of structural stuff or SEO, take the advice. If they think so because of the type info you provide and/or look and feel of the site, ignore it pretty much. If you love it, there are others who will love it too. You don't need everyone to like it, you want some people to love it a lot. Just don't load it down with banners - they are at best distracting to visitors, their eyes won't know where to look with all that flashy stuff. If you think of your site as a room, banners can be the art on the wall, never the furniture.
If there is anything you always wanted to know about casinos but still don't know, research it. Others will feel the same way. Make it available on your site.
It will be a hobby at first, then a part time job, and hopefully at some point you will have the choice to make it full time.
Good luck!