Hey

I've already got a pretty established website earning some decent money from Adsense. Now, i've been reading about affiliate marketing and the massive potential it has for income.

Now, the niche i am in, acne, has tons of affiliate products out there, so would it just be a simple matter of adding a banner on the side or a review page?

That's what I do. I also write articles and slip in an affiliate link to a relevant product.