First step to do this is
hey guys download mozilla firefox 3.6 and install two addons "NoDoFollow" and "SearchStatus"
"NoDoFollow" -- Just a simple extension to highlight links in a page according to nofollow / dofollow status.
SearchStatus - Display the Google PageRank, Alexa rank, Compete ranking and SEOmoz Linkscape mozRank anywhere in your browser, along with fast keyword density analyser, keyword/nofollow highlighting, backward/related links, Alexa info and more
so if you are building backlinks then you will come to know which are DOFOLLOW AND NOFOLLOW LINKS...SO YOU WONT WASTE TIME LINKING TO NOFOLLOW LINKS COZ SEARCH ENGINE WILL NOT CRAWL THEM
search google.co.in for terms indian classifieds,free classifieds and see alexa rank and page rank and start posting
you can also place Free classifieds ads on http://www.chillyads.com