I have 4 product review sites. What should I do to rank them well?

I have purchased 4 different domains for 4 different clickbank products 5 months ago, and I wrote 1000 word articles for each of them and published them 5 months ago. My domains are like the following:

1. productname + review .us
2. productname + review .info
3. productname + review .net
4. productname + review .net

I had purchased a little backlinks back then. And all my target keywords are like the following:
1. product name
2. product name review

I checked all of these keywords on google adwords keyword tool and they all have 1k-10k search volume per month.

And today I've checked the rankings on google. And all of my rankings for target keywords are in top 200 rankings. The best one is on 44th ranking on google. But all these websites still have zero visitors.

What should I do to rank them well on google, if I get them to first page of google, I guess I will start having visitors for these websites and hopefully some sales for the products I promote. What do I need to do exactly in order to rank these kind of websites in 2017?