Keep it clean and professional. If you link to your Twitter account from other social media platforms (think LinkedIn), be careful in
what you tweet. Many employers are now checking social media accounts of potential employees before deciding whether to hire them. If you need to vent and be a potty mouth, consider a pseudonym account.
Use hashtags (#). Join the conversation by including these in your tweets.
Do not blindly follow everyone. Twitter is not a popularity contest (for most folks anyways). Following everyone leads to clutter and spam. Auto following will get you lots of followers. Many you would not want to have your mother see.
Be active. Twitter is a real-time, 24/7 conversation and those who do not keep up with at least minimal participation every week will fall behind very quickly.
Pub your stuff. If you are using Twitter to further your career or make your viewpoints known, you need to get people to your content. Add your Twitter handle to your LinkedIn profile and email signature as quick and easy to get it out there.