A tweet only has 140 characters; with such a small amount of characters at your disposal, you need to make the most of each one.
The perfect tweet consists of three main parts: your message, a link and blank space. Here's what each section should include:
Call to action: Tell readers what you want them to do.Hashtags: Include one or two to increase your reach among people who don't follow you.Tone: Use your own voice, but in a professional way.Format: Use a mix of headlines, questions and statistics to drive clicks and retweets.
Shortened URLs: Bit.ly links earn the most retweets.
Leave room for at least 20 characters at the end of your tweet so retweeters can add comments.
Check out the graphic for more information...
Via Lauren Moss, Nate Ludens, John van den Brink