First you have to analysis your site.
Is all Onpage done correctly like: Robots file, Sitemap, 301 redirection , 404 error, content of site, H1 tag, Image tags etc.
and than Do Offpage work in a system.
Directory submission, Social bookmarking, Forums posting, Blog posting and commenting etc.
These are the some more thinks that you must remember during off page
1. use a different definition with each keyword and it must be relevant.
2. don't do over promotion of site or keywords. or over submission in a
and all the content must be unique and relevant or also stuffing of targeted keywords.
To increase my website ranking I follow these simple steps-
I have registered my website on google and bing local, webmaster and analytics, then started directory submission, social bookmarking, article posting, blog commenting etc.
I think following these tasks regularly can definitely get better results for your keyword ranking.