What really works when trying to sell by email?

I've been online over ten years now. I wrote one of the
first books on Internet marketing back in 1995. While I
started as an Internet skeptic, I now make 95% of my
income from email alone. I've used email to sell well
over one million dollars in e-books in the last 3 years.
I've also used email to --

-- make $175,000 in one year teaching e-classes,
-- drive one of my books to the number one best-seller
spot at Amazon,
-- sell high-ticket, membership-only teleconferences,
-- raise $50,000 in one day for e-consulting,
-- make $2,000 in less than 12 hours selling an e-book
I didn't write,
-- make one man a millionaire (with just one email), and
-- find the love of my life.

So, what have I learned from how to sell by email?

1. Long copy sells. Anything sold with a short letter is
either not going to sell or is going to lead people to a
longer letter on a website.

2. Subject lines that are personal, curious or newsworthy
work better than ones that convey a sales message. "From
Joe" will get more people opening my email than "New
software removes wrinkles while you sleep." (Well, THAT
latter headline might work, but I just made it up.)

3. Margin width is more important than paragraph length. I
keep my messages to 60 characters a line max. People are
reading email on their phones and palmtops. The email
needs to be visibly attractive on all screens to get read.

4. Freebies increase sales. The more people can get for free
when they buy the main offer, the more they'll buy. Since
the Internet began as a free service, most users have a
"gift culture" mentality hardwired into them. They expect
freebies. It's the old "psychology of the second interest"
working triple time online.

5. Text rules. HTML in email doesn't work. The vast
majority of users prefer their email in text-only format.

6. Repetition works. Repeating the main offer in the email
gets more sales. Far more people skim email than read it
word for word. Repeating key points assures the skimmers
will get the message.

7. Testimonials sell. I've sent out email that was entirely
made up of endorsements. Real people conveying their own
benefits encourages real people to part with their money.
An example is at http://www.mrfire.com/hypnostories.html

8. Hidden selling works better than direct selling. Due to
all the spam filters and the amount of spam, period, direct
selling in email will often be impotent compared to an email
containing a story or "teaching tale" that does a soft sell.
This is where Hypnotic Writing comes in handy. See a
quick example at http://www.mrfire.com/0057.html

9. Unusual openings work better than headlines. I'd rather
start an email with a story already in progress than with
a traditional hard-hitting headline. I may weave a headline
into the body copy later, after I've fully engaged the reader,
but not right up front. Headline openings tend to turn off readers. See an
example at http://www.mrfire.com/seedmoney.html

I struggled to come up with one more point so I could have
a "10 tips" article for you. But the truth is, no one knows
for sure what will work online, and I'm still learning, too.

So I'll let *you* supply the missing last insight.

Go for it!