In an email you should always use a greeting to send to the other person to show respect. ex: Hello Sarah,
In the signature have useful and helpful information like a name and maybe your grade if school email. ex: John Smith Grade 10
Use smile and wink faces only when appropriate. ex: Have a nice day! :)
Make sure to use manners read the email out loud to make sure it doesn't sound rude. ex: Would you please let me know soon?
Be sure to be concise and to the point don't make the email longer than it should be. ex: I am emailing you to let you know I won't bet at the event Friday.