Humans love to see progress. It’s why we invented calendars, clocks, and mile markers. We like transparent beverage bottles so we can see exactly how much is left. Progress bars that are displayed when downloading or transferring a file exist for the same reason. Progress is calming while the lack of it is extremely unsettling.

A multi-step checkout should be treated in a similar fashion. Nobody likes grappling in the dark. You need to show your customers the progress they’re making. Have a progress bar at the top of the page and highlight the current step they’re in:

Cart  –  Shipping  –  Payment  –  Review and Confirmation 

The example above shows a customer that they’re in the payment stage. They’ve already viewed the cart, filled in shipping details, and only the order confirmation step is left. By showing customers the completed steps and the ones remaining, you put them more at ease and motivate them to complete the process. It’s a subtle but powerful form of encouragement.

A few things to keep in mind:

• Make sure the checkout steps are clearly and descriptively labeled. Vaguely or wholly mislabeled steps do nothing but cause confusion. 
• The contents of each step should reflect the label
• Keep each checkout step distinct. Don’t combine steps like say shipping and payment. This only serves to complicate the whole thing by making the forms overly long which is in turn very intimidating.
• Have five or less checkout steps. Too many steps (say 10) would be very intimidating and actually discourage a user from starting the checkout process in the first place.

Examples

Adidas

B&H

Beardbrand

LL Bean