According to Evergreen Search there are 9 specific characteristics behind great tweets. It’s a perfectly OK list but it neglects some proven, measured ways to gain more retweets (the proof that you are tweeting well).
1. Images. Attach interesting images whenever you can. Pictures still tell 1000 words.
2. Links. Tweets containing links are retweeted far more often than tweets containing no link. It makes sense – how interesting can one be in 140 characters? People who never tweet any links must be just talking about themselves, shooting the breeze or – mercy – sending inspirational quotes.
3. Opinion – strong, consistent, confronting – works.
Lots more advice about Twitter and tweeting on our site.