The thick of the 2012 holiday season is here. And if you’re a retailer, hopefully you haven’t just primed your in-store and online offers, but your mobile presence as well. According to comScore, consumers spent approximately $37 billion on holiday shopping in 2011—up about 15 percent from 2010. And nearly 51% of the U.S. population are avid mobile Internet users, according to 2011 U.S. Census department figures. If we put two and two together, it’s safe to say it’s going to be a busy holiday season for eTailers, and their mobile sites will be no exception.

While mobile commerce stats have been rising for quite some time, many retailers have yet to nail its optimal experience. The quick fix of mirroring an online site for mobile applications won’t help here. The trick is figuring out what your customers need most in their on-the-go lives—and acknowledging that your mobile technology and strategy are only as good as the behind-the-scenes commerce ecosystem they support. Your mobile app or site connects the customer with the product, but its success can be greatly affected by several non-mobile factors—especially during the holidays (or other high-traffic buying seasons).

The gravity of factors such as product availability, shipping and delivery times, and seasonality are compounded in the holiday conversion game—online, mobile and in-store. Not only can you expect to see an influx of new visitors, but also previous customers who have switched from site to mobile shopping. And remember, they aren’t shopping for themselves.

This being said, waiting until the day before Christmas to test and optimize mobile promotions or discount offers is too late to start converting visitors into paying customers. However, there are a few checks and balances you can plan for now to ensure that the next few months bring those revenue goals that have been dancing in your head. In particular, make sure you aren’t making any of the following five common commerce mistakes (and if you have, fix them quickly!).

Forgetting to Highlight Holiday Sales and Specials

Nearly every retailer has an abundance of sales and products planned for the holidays to both entice your current customers and bring in new ones. Hopefully you’re planning to deck your site out in a fun, festive style. Are you planning the same for your mobile site?

Many holiday retail consumers use their handheld devices to compare prices and promotional offers. Make sure you are clearly displaying buttons and items within your mobile-friendly site and navigation bar that will lead customers to seasonal hot-ticket items, so you steal their attention before a competitor does.

Concealing Shipping and Stock Status

During the last-minute holiday rush, shoppers who are reassured their precious presents will arrive in time are more likely to buy—regardless of pricing wars. Take a look at your mobile site and consider how this very important holiday shopping information is displayed on both product pages and the purchase funnel.

Specifically in a mobile environment, the impact that font size, location, showing/not showing, color of stock and shipping status has on website conversion rates might surprise you. While no single stock/shipping status strategy is correct for all brands, don’t be afraid to test it thoroughly and make sure your consumers are fully informed to make quick on-the-go purchases.

Forgetting to Integrate Product Reviews

Shopping for others isn’t always easy…and the stress of a holiday gift doesn’t make it any easier. While not all of us are the perfect present pickers, we do prefer gifts that our friends and loved ones (hopefully!) won’t return. So when it comes to holiday shopping, product reviews can have one of the biggest impacts on customer buying decisions.

As we know, with mobile real estate there’s a much smaller surface to play with. But not giving the option of reading product reviews on the mobile site can actually lead to higher bounce rates than desired. Remember that mobile shopping is a fast, on-the-go decision—the more information you can give a consumer, the better. Look at your product pages and determine where a mobile-friendly drop-down menu or selection for reviews can go. Even just having an aggregated “rating” or “star” system placed near the product is a green-light indicator of a great product.

One caveat, though: leave the product reviews for the pre-shopping cart phase. Once customers have clicked “Add to Cart,” don’t distract them with information that isn’t focused on entering credit card details and hitting “Place Order.”

Recommending Products Based on Past Purchases

Behavioral targeting and product recommendations—especially in a very personalized mobile environment—are great ways to increase your average order values and your upsell/cross-sell opportunities, as well as keep your consumers loyal. You’re already expecting an increase in traffic and purchases with the holiday rush, which makes targeting, recommendations and segmentation both easier to achieve and a must-have.

But as holiday shopping ramps up, don’t forget: people are buying gifts, not shopping for themselves. If your targeting engine is set up to promote products based on past purchases made in the off-season, you’re wasting your time. Instead, target based on items they have browsed, clicked or added to their cart or favorites in the past few weeks. If your application or site allows for push messaging or email integration, follow up with messages around those products and/or promotions. And once again, make price comparisons and your sale items easy to find and navigate to on the small screen.

Poorly Designed Error Messaging at the POS

Imagine your prospective buyer with his smartphone in one hand and credit card in the other, precariously typing his card number, expiration date and security code with his thumbs. He hits the submit button and BOOM—no dice. An error has occurred; was it a wrong number? Wrong zip code? Invalid code? The real question is, does your mobile shopper even know what happened? Or is he just giving up, leaving you with yet another abandoned mobile cart to add to your analytics report?

Testing error messaging options is an important component for any site, but it’s especially crucial for small mobile screens. Most user-input errors occur during checkout, registration or form process. Careful attention should be paid to the location, design, display and wording of your error messages. If a mobile visitor can’t see or understand it, repeated frustrations will only lead that customer away from your site before the most important conversion of all—the sale.