Should I make so many different sites when affiliate marketing?
example for amazon products; should i make a simple review site with many products on it or make a site with a standalone review of one product? eg reviews.com or sennheiserheadphonesbuy.com

Domain containing keywords has high possibility to get on top in search engine. You got to have different domain but you can program 1 store at the back
No, dear
Build singles site and try to do good efforts for driving good traffic to it. And for this you need to make a good strategy first and implement it effectively.
So for this you can consult for a Network Marketing Professional.