SEO help needed?

hi warriors,
i am still new and have been quite confused on the SEO thing.

hope anyone can provide me some guidance and advise here.

i just start doing IM recently for less than 1 month and been trying to create a blog on a niche. i researched and found some low competitors and about 500 to 1000 searches per month keywords. I gather a few with not many search counts around 500/ per month only but with extremely low competitors (less than 500 with quotes around).
so i start to write around these keywords and been trying to rank for them.
i put these keywords each in the title on each of my blog post, and in the first sentence of my posts and just write about some related information.
then i ping my blog, submit RSS, and social bookmark the site.

after about 24 hrs, i can indeed see that my site is indexed in google after i check using the site: formula. but when i put the "keyword" into the search engines, i am not able to find my blog at all. there are only about 20 pages of competitors for 1 particular keyword but i am not able to find my blog for this keyword search. i am confused as although my site is already indexed, but i am unable to find the blog with my keyword, not mentioning trying to rank on the first page..
hope anyone can provide some advise on this.. thks a lot..