Affiliate Marketing Secrets

I have roughly about 7 keywords I would like to rank for, I have checked all with exact search on google keyword tool, they all say low competition, and all 7 keywords only get searched about 40 times each per month.
My domain is 2 worded and contains parts of both keywords.
If I set up a blog, how easy should it be to rank for these, its very niche, and how would I best go ranking for each keyword, like would a quality 1000 word article on each be enough.
Any advice please appreciated.