When you send an email you want to make sure that you use correct punctuation so that the person reading )(teacher, friends, family) know what you mean.
Make sure the email cant be interpreted as mean or rude.
Make sure that your name is in the email some how so the teacher/friends/family know who its from. Its important so they don't think its from a complete stranger
Also answer questions briefly. People don't want the long boring answers make them short, sweet and to the point.
DON'T attach unnecessary attachments. Some people don't want the thing that you think are cool. Also attachments can carry viruses.