Types of link Bait

Informational hooks - Provide information that a reader may find very useful. Some rare tips and tricks or any personal experience through which readers can benefit.
News hooks - Provide fresh information and obtain citations and links as the news spreads.
Humor hooks - Tell a funny story or a joke. A bizarre picture of your subject or mocking cartoons can also prove to be link bait.
Evil hooks - Saying something unpopular or mean may also yield a lot of attention. Writing about something that is not appealing about a product or a popular blogger. Provide strong reasons for it.
Tool hooks - Create some sort of tool that is useful enough that people link to it.
Widgets hooks - A badge or tool, that can be placed or embedded on other websites, with a link included.
Unique content hooks - This hook is intended for people that are in need of unique contents or articles for traffic or AdSense revenue. This became popular after Google implemented Duplicate Contents Filter and sites with duplicate contents saw fall in traffic. To use this hook, you have to create unique contents and give it out to Bloggers and webmasters with an obligation to put link back to your site.