I always say, look at what everyone else is doing and go in the opposite direction if you want to find ways to promote your site that are least competitive.
Virtually no one writes product reviews to GIVE to the owners of those products. Many people write reviews and only use them as content on their own sites. Big mistake!
For a powerful, high-traffic link you should write a full product review for a product you have enjoyed and offer it to the product owner to place on her site!
She will LOVE it and gladly link back to you, most likely. Not only that, she will place it in a high-traffic area of her site because it will help her sell more products!
Ignore this Power Linking tactic at your own peril. It works VERY well!