For the professional tweets, you can make observations about blog posts or articles you've read, and judiciously retweet a comment you found interesting. Keep in mind that what's written on social media lives forever. "You can't be one personality on the forums and then decide to clean up your act when you need to get a job," says Lipschultz.
Twitter is unlikely to give you fast results, warns Dib. So "you have to start it way before you need it."