To improve your site rankings, you need to focus on three things:
>keywords, keyword research
>content
>links
keyword research is the backbone of your organic SEO. if you choose and optimize for the wrong keywords, everything else suffers.
here are some good keyword research, suggestion and discovery tools I use:
https://adwords.google.com/select/KeywordToolExternal
http://tools.seobook.com/keyword-tools/seobook/
http://www.wordstream.com/
as for content, keyword research will fuel your content. author narrowly-themed pages around your keywords.
Here's a great article on content writing for SEO:
http://www.searchenginepeople.com/blog/intelligently-crafting-content.html
finally, links are super-important (both internal and external). links are votes for your website, and the site with the most votes win the "election" search results. you need to get relevant, authority websites to link to your site. best way to do that is by authoring great content. also, practice aggressive inline linking throughout your website, like Wikipedia does. the are the kings of internal linking and kings of the search results.
one of the best resources for linking is Wiep's link building blog:
http://wiep.net/
hope this helps you to understand what goes into good SEO and good rankings.
good luck!
My website is ranking okay, but not in first page yet, how can I improve my Rankings.

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