When Sylvan Goldman invented the original shopping cart in 1937, he had to hire models to demonstrate exactly how to use the new contraption. Customers at his Oklahoma City stores were accustomed to shopping with heavy metal baskets and didn't know what to make of the convenient wheeled carts.

Now, more than 60 years later, a new kind of cart—designed for e-commerce sites—also faces obstacles. It's not that customers aren't eagerly filling up their online baskets. On the contrary. But for some reason they aren't making it to the checkout line.

Depending on which survey you choose, customers abandon online shopping carts at a rate of between 25 percent and 77 percent. According to a survey by The Yankee Group, more than 75 percent of online shoppers have abandoned a shopping cart at least once. "I think it's really indicative of consumer expectations not being met," says Christine Loeber, a senior analyst with The Yankee Group. "Now that consumers have been online for a while the tolerance level isn't there. They expect online shopping to be more convenient than offline shopping. If not, why bother?"

Shoppers abandon their online carts for many reasons—in recent usability tests, the Ziff Davis Smart Business Labs found that turn-offs include poor site navigation, hard-to-find shopping carts, and time-consuming checkouts. The grim statistics, coupled with the demise of many high- profile e-tailers last year, make for challenging times in electronic commerce. Fewer sites may mean less competition, but with so many wary consumers, it's critical that your site provide a shopping experience as close to flawless as possible. "The key is to understand who your customers are and make sure you listen to what they want and need," says Loeber, "and to make those changes to ensure a simple and efficient online shopping experience."

To get your site on the right path—and to clear your virtual aisles of abandoned carts—we've assembled a guide to the mission-critical parts of an e-commerce site. Following these tips may mean the difference between a successful shopping experience for your customers and a missed sales opportunity for your company. We'll show you where to make the most radical changes to get customers through your site, into the checkout line, and to that still-rare territory of closing the deal.

1. CUSTOMERS CAN'T FIND WHAT THEY'RE LOOKING FOR.

Poor Web site navigation is a subject in and of itself, but for commerce sites it causes nearly 30 percent of all abandoned carts, according to The Yankee Group. Whether you use a tab system, like Amazon.com, or a directory, like Walmart.com, two things should govern your site's navigation—consistency and purpose.

Consistent design throughout your site makes it easier for your customers to find their way: Users can always click on product images for more information. Buttons use a consistent color. Links are always underlined. If your site is simple for users to understand, they will happily keep moving toward the checkout. Walmart.com's recent redesign came under fire by industry critics for being too boring. However, the changes made the site cleaner, simpler, and easier for shoppers to master.

Your site's navigational structure should also be determined by what your customers intend to buy. eToys (www.etoys .com) does a smart job of reflecting how shoppers think when buying specific toys. Customers can find toys by age, type, gender, and interest. With so many toys to choose from, eToys ensures customers find exactly what they're looking for.

Major Don'ts Don't underestimate the search box. For example, iQVC (www .iqvc.com) discovered that more than 50 percent of its customers used the search box to navigate its site. To make it even more effective, the company overhauled its search function so visitors can search by color, brand, ring size, and price.

2. THE SHOPPING CART IS TOO HARD TO FIND.

Whatever you do, make sure your site's shopping cart is a clearly identified link placed in the top right corner of the page, traditionally a high-click area. Moreover, make it available on every page in the same place. In our labs, users became frustrated when they couldn't find a site's shopping cart right away.

Also try bringing your site's shopping cart area to life. Sports retailer The Sports Authority (www.thesportsauthority.com) does that with its dynamic shopping cart. The cart displays the latest item added, allowing the customer to keep a running tab more easily. The company also made sure customers could click on the cart icon to start shopping. In contrast, Drugstore.com offers a live cart halfway down a left-side tool bar but ignores the top right convention entirely.

Major Don'ts Don't expect people to instantly notice items added to a dynamic cart. When shoppers add items, route them to a cart summary page each time—even if it seems redundant. This page indicates confirmation and invites the shopper to check out.

Also, if you use a dynamic cart it's best to list only the price of the last item added and the number of items in the cart. No one wants to be reminded that they're racking up a $600 tab while casually shopping. When they get to the cart summary page, customers then have a chance to remove items they no longer want.

3. IT TAKES TOO LONG TO CLOSE THE DEAL.

Shopping online is all about convenience, and nothing is a bigger pain than lengthy forms that extend the checkout process. No wonder people click away in disgust. While there may be no way around forms for the time being, keep information that you request to a minimum. Demographics are nice to know, but they can also kill sales.

Any good checkout process makes a distinction between a repeat shopper and a first-time buyer. Greet returning customers by getting them as close as possible to a single-click shopping process. Amazon.com leads in this area with the fastest possible checkout. The Gap (www.gap.com) also offers shoppers two clear shopping tracks, as well as an easy way to retrieve an account password.

A winning checkout system needs to be fast and easy. When your customers are ready to check out, keep the process short—at most four pages. Sites that spread out their checkout forms may be avoiding clutter, but they run the danger of stretching the experience out too long for the sake of clarity.

Major Don'ts Nothing is more discouraging than a navigational map that shows customers how far they are from finishing the checkout process but doesn't allow them to click on each section. The best, or worst, live example is Walmart .com's daunting checkout map: a full seven pages and an instant turn-off.

4. CUSTOMERS DON'T FEEL SAFE IN YOUR STORE.

Shoppers demand more than security online. Getting customers to trust you must happen throughout the site, not just when they use their credit card.

Establishing trust with your customers means making service a priority by giving them multiple ways to contact you and providing them with a timely reply. The GartnerGroup studied the top 50 e-tail sites and found that only 10 percent allow the customer to track inquiries through to resolution, and only 28 percent will acknowledge that they received your e-mail.

The human touch, especially in a faceless online world, is important to customers. Lands' End (www.landsend.com) has 250 sales reps ready to answer questions live online—and it pays: Their Internet orders end up averaging $10 more than catalog orders.

Ensure the privacy of your customer data in a clearly worded and easy-to-find policy, particularly if your site supports Web cookies—files that track and store user information. More than 20 percent of respondents to our Ziff Davis Smart Business reader poll said they had stopped an e-commerce transaction because they felt the site wasn't secure. Display the logos of consumer protection sites, like Gomez.com or the Better Business Bureau, that have rated your service. Also, make sure you spell out your encryption standards by using recognizable signs such as the VeriSign logo, and explain how credit card information is transmitted to your site's servers.

Finally, don't let customers get to the very end of the shopping process and slip them an unexpectedly high shipping cost. Spell out your shipping terms up front in a separate policy page that shoppers can find easily. Fifty-six percent of the customers in The Yankee Group study bailed out at the last minute when they found out the shipping charges were too expensive.

Major Don'ts Don't hide your customer service information. The more prominently you can post a telephone number, mailing address, and e-mail link, the more you tell people that someone is behind the screen ready to help. Make sure you provide answers to frequently asked questions—it will save time for both you and your customers.

5. BROWSING TAKES TOO LONG.

As long as shoppers use dial-up modems to access the Web, overall site speed will be a fundamental measurement to live and die by. Browse the top 10 Media Metrix sites with stopwatch in hand and you can almost feel the wind in your hair. You won't get a gratuitous 20-second splash screen on Yahoo or wait for graphic after graphic to download. The fastest sites help you get in and get out by making each subsequent click and page view as fast-loading as possible.

How fast is fast enough? There is no set rule, but for a fast and free look at how your site's speed stacks up, visit Web Site Garage, a Web site maintenance service, at websitegarage.netscape.com.

What shouldn't you do? Take a look at the Web site for furniture legend Herman Miller. Compare the main site (www .hermanmiller.com) with the company's new line of lower-priced office furniture (www.hermanmillerred.com). Herman Miller is a clean and fast site, while Herman Miller Red opens with a lengthy Flash production. In addition, the actual products—small thumbnails—are upstaged by the flashy opening graphics, making downloads a chore at any speed.

Major Don'ts Requiring the shopper to install a plug-in such as an audio player before they can even access your home page is a no-no. If you have to use a plug-in like Shockwave for animation, make sure you keep that part of the site separate and clearly marked. Nothing scares away a visitor faster than a software installation message before they've even committed to the site. And nothing stops shoppers in their tracks like a missing plug-in. Always give your site viewers the option to stick to basics and stay away from what they may feel are slow-moving waters.

ALICE HILL is a San Francisco–based freelance writer.