Please, please don't misspell the names of the people you're e-mailing. Often, that's an instant disqualification. Typos occur, but spellcheck can do wonders. Be sure to read every e-mail before you send it. You're not getting anyone's attention with emoticons and cute ways of spelling words wrong.
Also, even if you use a general template and personalize it to each person you send it to, that's ten times better than one huge PR blast. It can be annoying to read e-mails about cool stuff when you know hundreds of other people got the same email.