The principle is simple. You have something you want to sell—a product, a service, the benefit of your wisdom. You have a website, you have a Facebook page, a Twitter account. You’re constantly monitoring your page rank and tweaking your SEO. All valuable in their own ways. But if you really want to grow your business, you need to master email marketing, which has by far the most effective ROI of any channel. And to do that, you have to build your list.

This can be done a few ways. You can, of course, buy a list, but that’s both distasteful (unless you like the taste of Spam) and ineffective. Other than that, the internet is full of ideas, a large number of them from people trying to get you on their mailing lists.

But when you cut down through a lot of complicated marketing-speak, the principles are simple:

Make it worthwhile.

No one wants more stuff in their in-box just for the sake of more stuff. But people do like free stuff, and they’re willing to give their email address to get it.

Webinars

Can you talk engagingly on your subject for an hour or so? Promote a webinar through your website and social media, asking for email addresses to send more information. All you need is a webcam and confidence.

Ebooks

Ebooks have become hugely popular in the last couple of years, and for good reason. They’re not hard to assemble—you can recycle content that you’ve already created for other purposes—and they have a high perceived value.

Promotions

Everyone loves a deal, and if your margin can take it, offering free shipping, a bonus offer, or other promotion is a time-tested way to drive traffic, raise conversions and gather addresses.

Make it fun.

Contests

Offer to give away your product or something else of value to your social media subscribers or potential customers that your company comes into personal contact with.

Quizzes

Ever take one of those “What kind of peanut butter and jelly sandwich are you?” quizzes? Those are much more about engagement and information capture than they are about entertainment or letting you know the critical information that you’re a chunky, unsalted, whole wheat, strawberry sandwich. And yet people respond to them in droves. What’s better is that they forward them to their friends and “like” them on Facebook. Which brings us to…

Leverage Social

Encourage people to share with their friends, colleagues and others in their social networks. This may be one of the most powerful tools of all.

Make it easy.

Location, location, location

You’d be amazed how many websites hide away their email subscription call to action. Make it prominent, at or near the top of your home page. And if you have an “About” page, put it at the bottom of the text so that it becomes a natural action to click after visitors have learned more about you and your product.

QR codes

QR codes are a great and simple way to collect subscribers. Put codes on your business cards, in your print collateral, or on receipts. This makes it a snap for customers to opt-in to your list.

And Finally…

In the end, though, what’s going to make or break your email marketing isn’t your list, it’s what you’re sending out to the people on that list. Make it smart, make it funny, make it valuable. As we said above, no one wants more junk in their mailbox. People hold their breath a bit when they opt in to your list. Are you going to spam them? Are you going to sell their information? Be responsible, or you’ll find that your list will evaporate a lot more easily than it was built.