The best SEO tool for beginners is
Market Samurai. The training videos alone are worth watching even if you don't use the tool.
Don't underestimate the role of on page SEO to your efforts. Use a rank tracker to track your competition for keywords you are targeting, see what they are doing that you are not. Sometimes the smallest change can move you from page x to top 5 in Google.
Use keyword research to target keywords / long tail keywords you have a great chance of ranking, then once you rank well for those, move slowly toward more and more competitive keywords. Once the search engines understand the relevance of your site to certain keywords your rankings for other relevant keywords will improve.
There is alot you can do, alot you should do, but the best investment you can make to understand more about your sites and their performance is to get
Market Samurai and complete the free training modules.