Could someone critique my current status and monetization methods?

I've got a site which primarily reviews a type of product - we'll call them "widgets" for this argument. Anyhow, it has a total of 20 articles and each article is monetized using Amazon links. I'm very much an amateur and I can't help but feel that this site could be putting a hell of a lot more cash in my pocket each month. I'm not positive of that but confident enough to ask the experienced operators here. Maybe I should be using links from other sources as well, diversifying my portfolio, like clickbank, or maybe I'm doing just fine and don't realize it - I'll let you all be the judge. Here are some quick stats on the site. Let me know if you need anything else to form an opinion.

-Site reviews "widgets"
-total articles/posts =20
-each post has amazon links
-monthly visits = 11.5k
-average monthly amazon link clicks = 4k
-average amazon purchases = 165
-average monthly conversion rate = 3-5%
-average monthly pay from amazon = $350-$400

I guess I feel like either (1) I could be making way, way more given my traffic or (2) I'm doing better than I ought to be. Thoughts?

That's not a bad conversion rate, similar to what i get on my amazon site. I'd suggest writing more articles and building your site out. Spend a month's income on some high quality articles, and build on the authority your site already has.

I saw many here make more than that with a review site too
here's one journey maybe you find it useful , the guy made 800$ in his first 3 weeks !
http://www.blackhatworld.com/blackh...ssions/736030-clickbank-journey-4k-month.html

thats a normal looking stats actually