What is the most effective link bulding tactic?

I really don't know the actual answer but here a few things which I use to list building

- bookmarking
- article submit
- directpry submit
- press release submit
- web 2.0
- forum posting
- blog comment

Others include exchange link, guest writing, guestbook posting and document sharing. If you are a guest writer of a high traffic site, this is a good way to drive traffic to your site.

Blog posting,
Posting on blog networks,
WP theme promotion,
forum theme promotion on various platforms(Phpbb, vbulletin, etc...),
affiliate programs,
review sites,
disount/coupon codes,
link baiting,
and many more...