After all these years, email is still the most effective online marketing channel. Chances are you’re spending a lot of time trying to improve your search and social campaigns, but don’t forget how valuable email subscribers are. You need more of those.

How do you try to increase your email sign-ups? Share your ideas in the comments.

There are tons of things you can do to potentially increase your signups. To cover them all adequately would require a book rather than an article, but here are five quick hits from people who have put together larger lists of ideas (click any of the links for even more tips).

1. Make it easier to subscribe

BufferSocial says it was able to double email signups in 30 days by essentially having great content and making it easy for people to sign up. The content is a given, but how easy are you making it for people to sign up?

The company says it went from just using a slideup to using 9 different means of collecting signups: SlideUp, HelloBar, HomePage, PostScript, SideBar, Twtiter, Facebook, and Qzzr. The slideup still accounted for the biggest amount of signups, but the hellobar was a close second.

2. Leverage webinars

WordStream recommends utilizing webinars as a means of collecting emails.

“Use your webinar signup form to collect email addresses before viewers attend the advice,” it says. “Bonus benefit: hosting a webinar gets your name out there and shows that you are a knowledge powerhouse to be reckoned with and admired. Who wouldn’t want to sign up for your newsletter?”

3. Make your button interactive.

KissMetrics suggests making your submit button interact with the user.

“What if you made the submit button interact with and react to the user’s action?” it says. “One marketer did just that, testing a submit button with a red border that changed to green when the mouse was moved over it. His little conversion test resulted in a 40%+ opt in rate. The reasoning behind the color change is that it visually and subconsciously moves the user from “Stop” to “Go”, giving them the initiative to make that click.”

4. Make people feel like they’re part of something

Copyblogger suggests showing people that they are part of a group – a group that likes your emails.

“Why not show them what other people are saying about becoming a subscriber?” it asks. “This is especially effective if you can get a testimonial from someone respected in the industry. Don’t leave your testimonials to your testimonials page, put them where people need them. If you have a good number, display it. If you get a lot of comments, be sure your comment number is displayed at the top of your posts. If your number of monthly visits is reasonably impressive, make that prominent. If you have a good twitter following, highlight that. Large numbers immediately help new subscribers feel like they are becoming a part of something.”

5. Encourage Forwarding

Anyone can forward an email regardless of its contents, but it might not hurt to include a link in yours encouraging recipients to do so. It just might mean more signups.

“People respond well to recommendations from those they trust,” says WiredImpact. “As such, adding a simple ‘Forward to a Friend’ link in your email newsletter can help to improve the reach of your messages and add interested subscribers to your email list. Such a link can turn your subscribers into brand advocates, allowing them to send your message to their friends. Additionally, the recipients of forwarded messages will likely be fairly receptive to at least exploring your organization if someone they trust is sending it their way.”

Think about it. If someone is forwarding your email to someone, it’s because they think it’s specifically relevant to that person. If that person then subscribes, that’s a valuable addition to your list.

Don’t forget to get them to open your emails once they’ve signed up. Here are some tips for subject lines that might help in that department.

Do you utilize any of these ways of increasing sign-ups? Which ones? Let us know in the comments.