1.Be concise and to the point. Do not make an e-mail longer than it needs to be.
2. Do not attach unnecessary files. By sending large attachments you can annoy customers and even bring down their e-mail system.
3. Use proper spelling ,grammar, and punctuation.This is not only important because improper spelling, grammar and punctuation give a bad impression of your company, it is also important for conveying the message properly.
4.Make it personal. Not only should the e-mail be personally addressed, it should also include personal i.e. customized content.
5. Answer swiftly.Customers send an e-mail because they wish to receive a quick response.
6. Use proper structure and layout. Since reading from a screen is more difficult than reading from paper, the structure and lay out is very important for e-mail messages.
7. Do not write in capitals. IF YOU WRITE IN CAPITALS IT SEEMS AS IF YOU ARE SHOUTING.