Less Is More
This is one of the trickiest lessons, and it sometimes drives people crazy. When we write, we often have a tendency to use more words than we need. To write effective email marketing copy, you need to keep your words to a minimum.

If you write a 15 word sentence, can it be cut down to 10? Is there a shorter and more common word you can use instead? (like "fun" instead of "entertaining"). During my seminars I tell people to write a one paragraph bio about themselves. When they're finished, I tell them to cut out 15-20 words. This forces them to rethink every word. It's often a challenge (ask any news editor!). But with enough hunting you'll find those words you can delete. This makes your campaign more concise without changing the message, which is a big plus.

Keep in mind, the faster your email recipient can read the email, the faster they can act on your offers.