1.Title tag 2.Meta tags 3.Proper Use of Heading Tags 4.Alt Attributes on Images 5.Title Attributes on Links 6.XML Sitemap 7.Relevant Content 8.Link Building 9.Social Media

Really helpful tips guys and thanks for sharing.
I have to remind everybody though that content is very important.
The more useful and interesting content a website has the more successful it will be. This is because more people will want to visit it again and again, especially if a website is constantly adding more and more content on a regular basis be it articles, tutorials, news and opinion or whatever.

Here are some more SEO tips.
- Don't spam & Don't cloak.
- Don't use doorway pages.
- Pay special attention to your content.
- Put your competitors on your site and compare your positive points to their negative points (be truthful though).
- Syndicate your content.
- Use a good visitor tracking system like Google Analytics.
Write unique & interesting contents & use social bookmarking sites.

According to my experience so..

Article submission
Directory submission
Forum
Blog
Bookmarking
Link wheel
Are best.

The techniques for SEO are as bellow :

1) Domain & File Names
2) Keyword Phrases
3) Keyword Density
4) Title & Meta Description Tag
5) Meta Keywords Tag
6) Author & Robots Tags

It will depend on your budget range & nature of Site. Mostly forum posting is regarding as best as it is easy to handle , cheaper & less complicated & result oriented in long run.

Some best seo technique are define as below
-Higher Search Engine Rankings
-Lower cost
-Build Community
-Easy Web Publishing Solution
-Lower Costs
-Better Communication