It comes to something when website shopping carts are the topic of an online comic - or perhaps it's an example of how much more demanding users are today. Either way, The Oatmeal cast his amused, wry eye over website checkout processes and shopping carts in his recent comic (How to make your shopping cart suck less), and between the humour and the swearing, there's a few important, relevant points that any website's checkout process should consider.
Tell users what fields are mandatory - and make it really obviousThis maxim isn't just for shopping carts, but for any type of form capture. Users need to know what information you expect them to provide as early as possible; it sets expectations about the process. Telling the user what information you require after they try to continue really isn't very kind at all. Every forward navigation becomes a test for the user: have they delivered everything you want? Every missed field becomes a perceived slap.
It's a simple situation to correct: give the users a symbol to identify mandatory data capture. Put it in the same place relative to every input field or label. Make it really, really clear. Use colour. Use familiar symbols from well-known sites. The alternative is telling the user off when they try to proceed, or bogging them down with an intimidating screen. Telling the users what you wanted once they've clicked to continue is too late.
And if the information is not mandatory, why are you asking the user to provide it?
Don't insist on registration or account creation (state benefits clearly)Registration is a barrier to progress; users immediately mistrust a mandatory registration if they can't see any benefits, or are only planning in a quick one-off shop. So don't make registering with your site, or creating an account with you a required step in your checkout process.
If there are benefits to the user in creating an account with your site, advertise them! Clearly state the benefits of registration: if it's the only way to get package tracking, say so. If it's to help your marketing department, you may want to look at adding some other benefits for your users.
But in general, registration is a barrier to interaction. The irony of insisting on account creation is that it's doubtless driven by the desire to harvest user's details and allow marketing to build a relationship with them. It's the least likely approach to succeed. By forcing your users to register, you're pushing them away.
Well designed, consistent form layoutMany, many things have been written about web forms and label placement. Suffice to say that your website should make every effort to help your users provide the information you need. Make the form easy to scan, make it obvious, make it consistent, predictable. Misaligned fields, unclear labels, labels that may relate to different fields - all these things contribute to make your form difficult to scan, parse, and complete - making your users less inclined to do so. The harder it is for your users to checkout, the less likely they will be to do so.
The greater the number of users you put off with your layout, the fewer will complete the checkout process - the end result of which is to transform users into customers.
Make checkbox labels clickableWhilst we're talking about forms and data capture, let's get this one out of the way as well. Checkboxes and radio buttons are pretty small targets for users to click, particularly if they're not that adept with their mouse. Whether you have text labels or images associated with your checkboxes, make them all clickable, not just the checkbox element itself.
As a rule, it's a good idea to make all of your click targets as large as possible; it makes it more likely that the user will be able to click them first time, every time (if you need some science to persuade you, this advice is an implication of Fitts' Law applied to UI design). And - if you haven't got the point yet - making life easy for the user is what it's all about.
Capturing the same information twiceThere is no need for a website to require - to force - users to enter the same information more than once. Period.
Indeed, the only reasons I can think of are laziness and incompetence. In the digital world, it's the easiest thing to copy data, to duplicate information - it only takes a button click, a scrap of code. Any number of websites provide buttons to set the billing address same as the delivery address (or vice versa). Or to hide capture of those fields, or any of the numerous other ways of avoiding encumbering the user with physical world metaphors. Websites can be better than their real-world equivalents. They should be.
Summary: Make your shopping cart forgettableUltimately, all of this advice is about making your checkout process as simple, brief and forgettable as possible. In some respects, checking out should be to all intents and purposes unobtrusive; it certainly should not be onerous.
Users are busy; they've spent their time on research, they've made their decision to buy from you; and now they want to get through your checkout process as quickly as possible. Make it possible for them to do that, and they may remember your website favourably. Which is one step closer to them buying from you again.