New to seo tools... Using MNF.. Anything better?

I'm trying to market a review site that basically is an affiliate site with some real review content as well that I'm writing. I'm written several articles and got them published at a few of the larger article sites. I just found a copy of MNF and have been hunting keywords to try and target etc. But I'm not having a whole lot of luck... I've found maybe 15-20 keywords but that's about it. Is there anything better for this purpose?

Thanks...