By Thierry Costa

Every time a new smartphone or tablet hits the market, consumers are given new opportunities to figure out how these devices can help improve their shopping lives.

Looking for products and information plays a big role in day-to-day use of smartphones and tablets, and their manufacturers are adding features such as larger screens and stunning high-definition display to improve usability.

However, ecommerce marketers still need to make sure that their mobile Web sites overcome the challenges of browsing on small devices with limited bandwidth.

Site search has become the key method of finding products for mobile users, and plays a major role in generating conversions: site search users typically convert at a higher rate.

Therefore, improving mobile site search should be on the top of every online retailer list of must-do mobile Web projects.

Here are some insights into how to make mobile sites more search-friendly:

Super-size the search box. The search box should be easy to find on any regular Web site, but an easy-to-find search box is even more crucial on a mobile site.

Display it prominently at the top of the mobile Webpage. In fact, it should be one of the most obvious features on the page.

Use Auto Complete. Site search features for mobile users are all about saving time, and helping shoppers get to products faster.

Auto Complete, which suggests possible terms when visitors start typing the first letters of a keyword, helps your mobile customers find what they want, with less typing ? and less chance for errors.

You can show the possible terms in a drop-down menu to save space on the mobile screen. Ranking the terms by the most popular keywords can further increase clickthroughs.

You should also consider bumping up the usability of this feature with Rich Auto Complete, which displays the name, image, description and price for the most relevant products within search results.

Display refinements as expanding facets. Refinements or facets can very much improve usability of search on a standard Web site, so you want to make sure they are also available for mobile users.

On a standard Web site search results page, you have a lot more room to play with ? you can put refinements on the left-hand side of the screen or at the top.

On a small screen, it makes more sense to show expanding lists of refinements. These can be displayed with JavaScript, so they expand immediately when the user clicks on them. 

Make use of the bottom of the page. It is a good practice to include sort options, pagination, related search and another search box at the bottom of the page.

By putting these features at the bottom, you will be able to show as many product results as possible above the fold, and users can conveniently access other search options.

Conduct multivariate testing. Consider a mobile site search solution that allows A/B testing on your search results pages for more insights.

Even minor changes in search box placement or refinements can make a big difference in whether your visitors convert at a higher rate, and testing is the only way to determine which search options make sense for your mobile users.

Point QR codes to search results. Mobile shoppers like to use QR codes to find out more about products and special promotions.

Consider creating QR codes that point to mobile product pages, which can help customers search for products of a certain type or brand.

Such codes can help jump-start the search process and encourage mobile users to dig deeper into your product catalog.

Create banners related to specific keywords. When mobile customers search for a brand name or product that is on sale, include a keyword-driven banner at the top of the search results page to highlight that promotion.

Keep monitoring mobile visitor behavior, so that you know what is working and not working on your mobile site.

Change is coming fast and furious in the mobile commerce world, making it imperative that you understand what keeps your mobile shoppers on your site and shopping more often.

Thierry Costa is vice president of marketing at SLI Systems, San Jose, CA. Reach him at .