Mix both big and small letters in your text. Put your reminder in the P.S. after your signature. Studies show that the P.S. gets read more than the body of your message. Use the spell check. You represent one of the most prestigious universities in the world, be sure your written communications reflect this expectation of excellence.
Attachments Use attachments when sending considerable supporting information.
An attachment larger than 50Kb can impact download times excessively. Some programs will do this automatically. Don't let your signature become longer than your text, however, especially if you include catchy quotes, drawings, etc.