Email marketing is a complex topics. Fortunately, it’s a well-explored topic. Just about every mistake has been made, and almost every approach to email has been tested by a myriad of different marketers in different markets.

So what actually works? And what pitfalls should you avoid? Here are six do’s and don’ts.

===> #1 – Don’t: Mix Bought Lists with Opt-In Lists

Purchased lists and co-reg lists are going to get a much lower open rate than opt-in lists. You could also get a higher spam complaint rate. Having them on the same server could cause your purchased lists to damage the deliverability of your opt-in lists.

==> #2 – Do: Split Test

Is HTML email better or text email better? Is a big black headline better, or just leaving your first line as it is? Are short emails better or long emails?

You’ll never know unless you test. Split test everything you can about your list.

==> #3 – Don’t: Rush Your Subject Line Writing

Don’t spend five minutes writing your subject line. Spend half an hour on it, at least. Write twenty different subject lines, then pick the best one.

People often write the body of the email first, then write the subject as an afterthought. It should really be the other way around. Pay more attention to your subject than anything else.

==> #4 – Do: Build Trust over Time

The main purpose of an email list should be to build trust with people over time. Establish credibility with them. Get them to feel like they know you and that they can trust you to deliver value in your products.

Don’t just sell, sell, sell. Deliver value and build trust. In the long run, you’ll sell more this way.

==> #5 – Don’t: Use Double Opt-In

Most autoresponder services are going to push you to use double opt-in. It makes their job easier. But it really makes no sense for you as a marketer.

Yes, you get higher open rates and lower unsubscribes from double opt-ins. But the TOTAL opens from the same number of initial subscribers will always be smaller.

You will basically never make more money with double opt-in than single opt-in. It makes no sense to use double opt-in.

==> #6 – Do: Send a Variety of Different Kinds of Emails

Mix up your emails. This helps keep people from getting bored with your emails.

For example, your bread and butter email might be tips on a specific topic. But every once in a while, do an email just on answering questions mailed to you this week. Every once in a while, analyze a product or comment on a news story. Every once in a while, share a personal story.

It’s okay to have a primary style, but varying things up can make things a lot more interesting.