Which SEO activity nowadays is better for better ranking?

[frank]

Thanks to all for your valuable contribution about SEO aspect :
I did following things regularly like :
1) Forum posting
2) Directory submissions
3) Classified Submission
4) Social book Marking
5) Blogging
6) Blog commenting
These Followings work in a week
1) slide/image and video Submission
2) Social media activities
3) Article Submissions

But Still Faced Ranking Issue like huge fluctuation and most time website going down i don't no why?? so please suggest some advance activity to improve ranking. Thanks !!

Forum posting, social bookmarking, blog commenting, social shares they do not effect SEO at all. They are only good for audience outreach.