How i earn through blog?

you should know these...
1) your blog topic is too narrow... instead of nano... you select cars... supercars etc.
2) go to reputed blog and give valuable links to your blog.
3) use feedjit and counters for your blog. site meter , statcounter. than you will know from where visitors coming.
4) add valuable content.
5) research keywords on nano get 12,000 searches but that consist ipod etc.
http://freekeywords.wordtracker.com/
or any other tool.
add keywords with less competition with higher search volume.
6) write few articles on some site.
7) sign up for few sites like kontera, bidvertiser, adsense others.
8) answer on yahoo auto for your blog.
9) use good blog theme.
10) add feedburner and email subsciption on your blog.
11) use wowzio so, visitors stay longer on your site.