First impressions - the preview panel
We would all like to think that everyone who receives our emails takes the time to read every word and appreciate our hard work, but the truth is the delete option is only a mouse click or key stroke away unless we can capture their interest almost immediately.
That is why it is important to ensure that the recipient will judge your email positively from what they see at first glance (i.e. the preview pane). Try to summarise the email clearly and concisely in the subject line, if you have any images position them first as people tend to scan for them before focusing on text and in text don't hide your point away in a long paragraphs which they might never finish reading. Be bold and remember that you are asking people for their time and effort and no one what's to waste either.