Responsive design is design that looks good on mobile browsers alongside standard desktop browsers.

In a world where more and more people interact with email on their mobile phones: on public transport, at lunch, over a coffee, wherever they are - responsive design is increasingly important.

It's also becoming easier and easier to get right. Here are three ways to go about it:

1. Get a responsive template from Themeforest. Most templates there are already responsive so you can often cheat your way to a headstart taking this approach and either customizing a base template or rolling with it as-is.
2. Use the email marketing boilerplate. This gives you a framework for targeting mobile devices and provides a raw canvas for you to customize with a lot of tricks to get it right.
3. Litmus is a great tool for testing your HTML email across a range of platforms you otherwise never could. You can view your email on iPhones, Blackberries, Nokias alongside desktop clients and make sure it's all looking perfect.

Litmus recently blogged about an example from Tsubo. Using a responsive design (shown below) Tsubo were able to increase their click-throughts by 10% - an impressive impact for a few extra lines of CSS!