Smashing Magazine's recent article on some fundamentals of usability for the ecommerce checkout process gives some incredible insights. I'm a big fan of Smashing Magazine. Their articles are usually top notch and give a lot of useful information, even if their sidebar ads are a little excessive. This article goes above and beyond, offering 11 tips based off an extensive usability study they conducted last year.

While the original article is worth a read if you are a designer or have a shopping cart on your website, I will give the condensed version here.

Make your checkout process linear - don't sidetrack the user and then send them back to a previous page. It messes with their Zen.

Add descriptions & examples to form field labels. Useful ones, not just "First". Give an example, or a sample image of where to find the info.

Avoid ambiguous and contextual words. Don't say "Continue" or "Back", but rather "Shop More" and "Checkout Now".

Visually reinforce all sensitive fields. We know it's secure, the user doesn't. Put trust badges next to the sensitive info (the credit card).

Don't use apply buttons. Users think buttons are good for one thing - submitting a form. Use Ajax if you need an intermediate step, like calculating shipping info from a zip code.

Format credit card expiration date fields exactly as they appear on a card - 01/12.

Use only 1 column! I can't say this one enough - multi column fields confuse people. A lot.

Use shipping address for billing by default. Most people buy things from and for the home. _Hide _the shipping info until the user explicitly asks for the addresses to be separate.

Make your error messages clear and next to the fields with errors. Putting the messages at the top just isn't good enough.

Registration should be optional. We've known this for the better part of a decade, yet people still try to force it. Ask the user to register after they have checked out.

Don't require unnecessary information. Another duh we've known forever, yet I still get asked for a phone number. Uh, why do you need digits when I'm buying an ebook? A laptop, sure, but not a $10 digital purchase.

This article is well worth a read. The author states they tested over 500 usability principals and published 63 guidelines, but didn't offer a way to find the other 52. For now we'll have to settle for these 11.

But with shopping cart abandonment rates of 60-80%, these are gold.