Hello Friends,
I have been working on one of the SEO project from past few months and by working consistently on this I had achieved my first target that is to bring all the keywords on top ten position but now I am focusing to bring these in top 5 position and some of the techniques which I am using are directory submission, social bookmarking, forum posting, blogging, article submission etc., Still by using all these techniques the keywords are not yet stable on their position for example one of the keyword was on position 4 and now it has dropped down to position 7.  Please suggest some techniques which can be helpful to bring all the keywords in top 5 positions and make them stable.
Thanks.

You have to do more seo effectively and be patient.
All the best.

You see, it's very difficult to stick to a SERP ranking. Fluctuations in search results (as a result of rigorous optimization by your competitors) makes it really hard for webmasters to stay glued to a high SERP position.
Try concentrating more on building quality traffic (blogging, guest blogging, social bookmarking, social networking, niche forums) which will boost your rankings automatically.
Guest blogging works for me, With keyword country as my partner, I am able to find niche related blogs easily to comment on.

You must, however, keep working on on-page and off-page optimization techniques consistently and religiously to avoid steep falls.

Agree with newon. You have to do more seo activities.

I have been working on one of the SEO project from past few months and by working consistently on this I had achieved my first target that is to bring all the keywords on top ten position but now I am focusing to bring these in top 5 position and some of the techniques which I am using are directory submission, social bookmarking, forum posting, blogging, article submission etc.

You can use the advantage of blog commenting and keyword research to help you rank your keywords but make sure that the keyword that you use is relevant on your website to prevent decreasing of its ranking.

Just be patience and do manual building..make quality backlinks and donot use any software for backlinking.