Explain how you would compose an effective email message?

I'm not sure just what you mean. If you're simply looking to inform, have all your facts, put them in a logical, possibly entertaining, manner and communicate them clearly. If your goal is to persuade someone to change their point of view or do something (like vote for a particular candidate), once again have your facts in order, acknowledge the opposing point of view, and finally hammer home your opinion. You'll want to conclude either an informative or a persuasive piece with a conclusion that gives some closure to the topic. Hope this is helpful! Good luck.

Explain how you would compose an effective email message?
Effective? Do you mean persuasive? You would start out by telling what you are writing about and then you would place 2 to 3 persuasive ideas as to why you are on this subject. Then you would close it off with what you think the outcome or achievement might be.