When I check my website in Google Webmaster Tools, then keyword 'angeethi' is shown to be at the 3rd position in terms of significance. But when I search for 'angeethi' at Google, then the website doesn't appear even in top 15 pages for 'angeethi' keyword. What can be reason behind this and what should be done to improve this?
If I have the keyword "Apple" as the prominent keyword in my website, does that mean that I shall rank better than the official Apple website? It does not.
You need to work on your SEO skills to get your website ranked higher. As a start, I shall suggest you to add more content to your website, and optimize its page load time. Start building quality links to your website, and it shall soon rank in time.
A factor is how your keyword is related from an outside perspective to your domain. If your link appears on other places in the context of your keyword it ranks the site higher.
For example an article on a blog (ideally solely writing about your keyword context) with your link you intend to rank for.
The higher the page value of the linking site the more influence for the link and its keyword context.
Another factor might be spider accessibility. Easy to read code and fast access is a plus.
However, take a simple keyword for example, "computer". Maybe the majority of sites that ranks high for this keyword rank that high because they appear as most logical for google in the context for "computer"
Beside that, these two links might help: http://support.google.com/webmasters/bin/answer.py?hl=en&answer=35291 http://www.youtube.com/user/GoogleWebmasterHelp?feature=watch
At the 3rd position in the Terms of significance at your Webmaster Page Means that you'll rank higher than other sites. AFAIK It means that the keyword 'angeethi' at the top 3 of your sites (in the terms of quantity).
You must consider the popularity, quality, trustworthy, and BIG 'G' factor of your sites among others.