Keyword Practice & Keyword Tools!

I am currently trying to better the SEO for my website.
I used the keyword tool on google adwords to find keywords/phrases that are relevant to my website. After searching several "Exact" keywords relevant to my website, i choose 10 keywords with alot of monthly searches, but not too much as im starting out & i think it will be slightly easier to get better rank in the less used keywords. I also checked the competition on each keyword/phrase & went for low - med competition. I then added these keywords into my website/webpage & then started to build article, blog, forum & web-directory back-links to my website using the keywords/phrases i choose as the anchor text in the backlinks.

This is as much as i have done so far regarding keyword targeting.
Is there anything about what iv done that you would consider wrong?
Is there anything else that i should do to improve what iv done already?
Is there something that im not doing in regards to keyword targeting that i should be doing to help improve my results in the top search engines?

Please comment on this thread with your thoughts as im quite new to the SEO game & will appreciate any help, tips, information, etc.. given to me! Thanks!