The Twitterverse doesn't have many rules, but there's such a thing as Twitter etiquette. Writing Tweets of 140 characters or fewer isn't the only guideline. Your experience on Twitter will be a positive one if you keep the following tips in mind:
Say what you think or are doing.
In general, keep Tweets longer than one word so that your followers can understand you.
Listen to what your Twitter network is saying.
Respond to Twitter followers when you can add value to the conversation.
Update your status at least once a day.
Fill in your profile and biography so that other people know more about you.
Use your own picture as your profile photo. If the picture you use contains more than one person, make sure that people can tell which one is you.
Whenever you're referencing another Twitter user, use his name with an @ sign in the front so that the user can see that you mentioned him and so that other users see who you're talking about.
Use hashtags to give context to updates that may not make sense otherwise.