What are the best practices on Twitter ?

Using not more than 2 hashtags every tweet.
Keeping the tweets around 100 characters. Make your tweets crisp and hitting.
Schedule and plan your tweets with the help of Buffer or TweetDeck.
With the help of Twitter Advanced search, you can manage your Twitter Marketing activities.
Keeping a check on Twitter Analytics to know what could be done to improvise the strategy.

I'll add another. Don't just "quote tweet" link headlines. If you're going to quote tweet a link, ad something valuable to say rather than copying and pasting the header text.

Oh and:

1. Don't RT yourself.
2. Don't make too many threads
3. Don't use lists to be obnoxious.
4. Don't expect a follow-back if you aren't making good content.
5. Don't do follower-churn.

2. Don't make too many threads
3. Don't use lists to be obnoxious.