Well, you’re going to need some passion for what you’re writing about. Hence, why you need to be interested in what you’re going to promote.
There is no magical “get rich quick” with affiliates scheme. You like something; you teach other people about it; and then you reap the rewards of people liking something you do.
You can’t just put up a casino website and expect people to be throwing money your way.
Now, what type of site are you trying to promote? Casino? Poker? Sportsbook? Bingo?