Don't underestimate the power of following grammar rules as you build your personal brand. When you communicate with others in the business realm through writing, use a dictionary and style guide to check your spelling, punctuation, and grammar in e-mail and handwritten correspondence. Spell- and grammar-check software features are good in a pinch, but they are prone to context errors. One of my pet peeves is using the word “that” to reference a “who.” A good (and concise) resource is The Elements of Style by William Strunk and E.B. White.
The easier you make it for people to get in touch with you, the more likely they will. A great way to do that is to make your contact details highly visible on all your communication.
A full electronic “signature” including your name, company name, mailing address, phone number(s), website, and e-mail address should be on the bottom of every e-mail you send, including replies and e-mails sent from your mobile device. It's a simple courtesy that can make it easy for people to add you to their electronic address books, find your number when it's better to answer via the telephone, or locate your office address when they are running late for a meeting.
Signatures only take you a few minutes to create, but will save your contacts time because they won't have to hunt for ways to reach you. Not everyone inputs data into an address book routinely so if you don't send your contact details, they may not have them handy. I've actually given up trying ...