A few months ago, I wrote a guide entitled: 101 Writing Tips for Successful Email Marketing. In fact, many COPY TIPS subscribers have a copy. Since that time, I have worked on dozens of successful projects and have discovered some additional tips for boosting response.

1. Ask a question in the Subject line. This almost always gets the email opened. I suspect this is because questions are so much a part of everyday email between friends and colleagues. It's a natural way to begin a conversation. Just be sure your question is honest and straightforward — not cryptic, hyped, or suspicious.

2. Write a letter, not an ad. With the growing use of graphics in email, a lot of marketers are experimenting with formats that look more like an ad than a personal message. The fact is, an "email ad" is more likely to be deleted on sight than one that appears to be a personal message - even if that message is obviously promotional.

3. Don't be afraid to go long. In the early days of email marketing, short copy was the rule. But this is changing. For some offers at least, longer copy that tells a more complete story is doing better. This is especially true when a transaction is involved, such as a subscription or sign up.

4. Beginning, middle, and end. Most click-thru responses will come from the hyperlink at the top, bottom, and middle of your email message - in that order. A lot of marketers forget the middle hyperlink. Don't. Your response rates will suffer.

5. Show a picture. For graphics-enhanced email, consider including a picture of your product. This will tend to lift response. Of course, if your product is intangible, you'll have to think of an interesting way to present it as an image. But, trust me, it's worth the effort.

6. Link the images. If your email contains pictures and other graphics, be sure to hyperlink them. You'll be surprised how many prospects will click on these to respond.

7. Drop-text images. A drop-text is a text message that appears when your curser hovers over a graphic. This is common on web pages. In email, this technique works like a picture caption or sidebar that displays as your prospect interacts. Very powerful.

8. Bribes work well. An offer of free shipping, a discount, an invitation, or a free gift is extremely effective in email marketing. For my money (and my clients') information premiums — white papers, guides, checklists, downloads — work best.

9. Add a toll free number. Most prospects will click thru and respond to your offer online. But some prefer to call and speak with someone live. A toll free number will often boost response.