1. Be concise and to the point of what your saying this is important so they know what your talking about.
2. Answer all questions, and pre-empt further questions because they might find it rude.
3. Always use proper spelling, grammar & punctuation because you might confuse them.
4. When your emailing make your conversation personal so they feel comfortable and doesn't seem like everybody could see and you wouldn't care.
5. When emailing answer swiftly Which means you should reply right away and not take a long time.