I think you should play with these tools. List at the top of me, for you are:
1-Google for search-good picture, you can analyze and see which keywords are the highest rise in search%
2 – Google Trends – show you the latest trends in your niche research
3-Google Adwords-go to reporting-> keyword tool-> placement tool (it will provides you with a list of targeted keywords match your website)
good luck, and you can visit the website for Affiliate marketing-list for more tips.