I'm Doing Seo of Of my site every week 7 to 8 avtivity like bookmarking submission,Directory submission,Forum posting ,Blog commenting,profile creation,Blog posting,article subbmission,Search enginbe submission ,Link Reinforcement,Classifids Submission,Document sharing,Press release and many other activities but still my keyword ranking is stable and not improving ranking.
Did you research your keyword? When you write any article uses your main keyword somewhere. And content is king so be aware about your content.
It can take some time for all of this to take effect. Keep doing what you are doing and in a couple of weeks/months you will see some movement.
I'd suggest you keep that up, and do some research on the competition, on where they are getting their backlinks from and see if you can get them. I would also try outsourcing to mix things up (like buying services from seo marketplaces), and I think you should check out what PBNs can do (even though most people are 50/50 when it comes to using PBNs)