According to market researcher eMarketer, retail ecommerce holiday sales this season are expected to top last year's -- by over 15 percent -- with sales in November and December alone expected to reach $61.8 billion. Contributing to the increase in online sales, more consumers are using mobile devices (smartphones and tablets) to research products, comparison shop and purchase items online on the fly. Is your ecommerce site ready for the holiday rush? To find out -- and learn how you can drive more traffic to your online business and increase sales this holiday season -- check out these 16 tips from ecommerce and online marketing pros. 1. Don't wait until the last minute to get your site holiday ready. "There is nothing worse than getting on the back end of your designer's schedule or paying to have your project expedited because you didn't prepare," says Katie Childers, owner, ABitofWine.com, an online wine gift and accessories boutique. "We are sending all of our Q4 graphics needs to our designer [now] so we are ready to go for key dates like Black Friday and Cyber Monday.""Have everything -- any programming -- ready to go by November 1st," says Erik Huberman, CEO, Hawke Media. "Your landing pages, emails and ads need to queued up and ready to go when you know they'll be most effective," adds Will Devlin, ecommerce manager, ShopVisible, an ecommerce solution provider. To make sure you're ready to go come November, Devlin says creating a calendar several months ahead of time. 2. Make sure your teams, servers and partners can handle holiday traffic. "According to the National Retail Federation, 139.4 million consumers shopped on websites over the four-day Thanksgiving weekend in 2012 -- and several well-known online retailers experienced downtime and technical hurdles due to this overwhelming shopper response," says Devlin. To avoid losing sales, "ensure your website can handle traffic increases, especially when large promotions hit.""If you're hosted on-premises, review your past performance metrics against your seasonal forecast and ensure that you have bandwidth and capacity for the expected spikes," says David Chiu, ecommerce strategist, Elastic Path Software. Google +.