Be descriptive
When readers look at the “recent posts” block, or titles in their RSS news feed of our site, they don’t get the context of the article. All they see is the title.  Let it stand alone as a complete thought.
Bad example : Website tip
Good example : How to write a good post titles
Use Keywords
Some people use the search feature on this site, and many use internet search engines such as Google and Bing. Think about what a visitor might be looking for.
Bad example : 50 delicious vegetarian restaurants
Good example : 50 delicious restaurants in NYC
Shorter is better
When post titles get lengthy, they get cut off. Users look for concise, accurate titles…think of the news paper headlines.
Bad example : Read this article and you’ll know 70 ways to make a lot of money online!
Good example : 70+ resources to make money online
Use dates if applicable
Having a party? Put the date right in the title! Often a visitor will just come to the site really quick to verify the date of an event…don’t make it too difficult for he or she to find the really important information.
Bad example : Flag Day Celebration!
Good example : Flag Day Celebration – June 14th @ 1130
Examples taken from Cats who Blog