When writing an email keep in mind that the reader is busy
Subject lines are headlines. Making use of the subject line is the most important decision about an email. This is where the reader will decided to open the email or delete it. Never leave the subject line blank.
Make one point per email. Each point you make will require its own response. Separating each point into different emails will allow the reader to respond to each email with the appropriate response in the correct amount of time. If the questions are all regarding the same subject and need to be in one email, making sure they are clearly separated is important.
Specify the response you want. Make it clear what you what the reader to do, by stating when and how to get a hold of you. If there is no response needed, you can state that so the reader understands what to do. The clearer the response wanted from a reader, the more likely it is that you will get one.