How do you do that? Considering that retailers have more content about a specific product, how hard to you have to work to beat them?
They usually don't (have more content about a specific product). They have a few images, a short description and possibly some reviews, but that is it. They don't tell you the best ways to use the product, customers need to go trough many reviews to see if people like the product, etc.
You, as a reputable source in your industry (of course, you need to work on authority as well), can give people all that in 500 words. You can show them advantages and disadvantages of the product and because they don't consider you a seller, they will be more likely to buy from you (and people usually don't consider you a seller even if you tell them that you are getting paid for their every purchase, which is what you should do as an affiliate).
Of course, you need to get some authority (in the eyes of your visitors, not just in the eyes of Google). And, to outrank them, you need to build some links (I'm not talking 1000s here, a few hundred high quality ones is usually enough, but, it all depends on the niche).