Although the major holiday shopping days have passed, retailers should not let themselves grow lax in their sales efforts during the next few weeks. According to surveys by RetailMeNot, nine out of 10 U.S. consumers still have more gifts to purchase before the end of December, and merchants should be prepared to meet the demands of nearly 200 million customers throughout the country. 

Many of these consumers (88 percent) said they will wait until the last minute before buying everything they need, while nearly all parents (95 percent) will likely do so. Retailers should ready themselves for an influx of customers requesting expedited shipping for online purchases, as well as large crowds in their stores after December 20. 

One issue that merchants should pay particular attention to is the length of their lines. According to RetailMeNot's survey, 53 percent of respondents consider checkout lines to be the most stressful part of their holiday shopping, and 40 percent say the same about the crowds. Alleviating these feelings will rely on great customer service and powerful point of sale software that can quickly complete each transaction and keep a steady flow of customers in and out of the store.