Email might not be as shiny as social media and other emerging marketing channels, but it's still arguably the most powerful marketing tool around.

A recent study asked consumers which channel they prefer for receiving permission-based promotional messages. A whopping 77% said email. No other channel even scored in the double digits; only 4% of respondents said Facebook, with Twitter and mobile apps both scoring a mere 1%. That's a very clear message about how your leads and contacts want to hear from you.

So how do you maximize this old workhorse for new gains?

Sometimes the best way to learn what to do right is to consider what not to do. In that spirit, here are six common email marketing mistakes... and guidance on avoiding them.

Mistake No. 1: Neglecting Buyer Needs

Does the CEO of a major corporation in California have the same needs as a small marketing team in the Midwest? Probably not. Moreover, retail email volume increased 61% from 2007 to 2011, making for a very noisy environment. To slice through the clutter, 'you need to speak directly to your buyer.

Use segmentation strategies to target campaigns to specific buyers' specific needs, particularly their "pain points." By doing so, you'll position your company as a friendly one that's paying attention.

Mistake No. 2: Blasting the Same Message to All Contacts

Chances are, your interactions with prospects are not all the same. Some prospects may already be fans who follow you on social media; others may have never heard of your company before. What's more, you may well have more than one product or service to offer.

Email marketing is wonderfully customizable. Segment your lead list into different groups and customize your messaging to each. You'll see higher click-through rates—and more-engaged customers.

Mistake No. 3: Failing to Adapt Messaging

You've heard insanity defined as doing the same thing over and over, and expecting different results? Start paying attention to your response rates, and you'll prevent some of the expensive insanity that can result from a bad email marketing strategy.

Split-testing allows you to test copy and other variables so you can adapt your messaging, timing, and so forth based on response rates. Doing so boosts your open rates, making for more efficient campaigns.

Mistake No. 4: Not Linking to Your Website

You send out marketing emails to increase sales by increasing traffic to your website, right? So don't forget to include links to your website and to specific product pages in the actual email. In fact, research shows that the more links you include, the higher your click-through rate.

That said, we don't advocate loading your emails with irrelevant links in hopes of more click-throughs. Too many links will turn off prospects. Determine the right number by gradually adding more links until you hit the sweet spot that provides the highest return.

Mistake No. 5: Ignoring Mobile Email Readers

A recent Return Path study revealed an explosive 81% growth in mobile email viewership from October 2010 to March 2011. You can't ignore this trend. No matter how great your content is, if your prospects can't read it on a smartphone or tablet, it's not going to be read.

Making your email mobile-friendly is a bit tricky: You have to optimize it for multiple mobile operating systems (iOS, Android, Windows, etc.), all which have different requirements. But the mobile trend is unstoppable, so it's well worth taking that extra step now.

Remember that most mobile email readers will not automatically load images; even if they do load them, you have no guarantee that the images will display properly. So, design just as for non-mobile email: Use HTML text, use alternative text for images, and don't forget to include a plain-text version.

Mistake No. 6: Not Having a Strategy in Place

The No. 1 reason people unsubscribe from an email list is that they receive emails too frequently. Put an email marketing plan in place that strategically lays out when emails will be sent to each segmented group. If you see a spike in the number of people unsubscribing from your emails, the cause may well be that you flooded their inboxes. Look at the frequency of previous emails and compare unsubscribe rates; you'll most likely see a pretty clear window of time when you can email again.

(Image courtesy of Bigstock: Frustrated)