Black Friday—the one day or, as it is now, the string of days—is a make-or-break time for many retailers. The holiday gift-giving season is an enormous opportunity to make up a lot of sales for the entire year, and Black Friday is essentially its launch. 

But this opportunity also comes laden with potential pitfalls. Retail Dive looks back to scare up past mistakes—from slow crowd control to outdated mobile capabilities—that retailers would do well to avoid this year.

Mistake: Taking email for granted

While mobile use is growing in leaps and bounds and is becoming a primary marketing channel, old fashioned email, on any device, remains the centerpiece of digital communication. Last year research found that retailers were sending out Black Friday and Cyber Monday emails too late—while the majority of campaigns happened on Thanksgiving Day and Black Friday, open rates were the highest on the Monday and Tuesday before Thanksgiving. 

Retailers that don’t leverage email effectively are missing out. That means checking up on deliverability issues, and running email campaigns in a way that doesn’t overwhelm customers to the point of unsubscribing.  

Retailers should make sure that they understand all the intricacies of shopping cart abandonment, too, and communicate via email to cover their bases. Shoppers are finding handy ways to use shopping carts as a way to flag their desires, keep options open, and shop around. These behaviors yield data extremely useful to retailers, experts say.

“What consumers are saying is that they see the cart as a tool,” Jim Davidson, head of research for marketing automation provider Bronto Software, told Retail Dive earlier this year. “It really seems to be what they are relying on to make connections across different channels.”

Mistake: Ignoring what the data tells you

And that also means using data from customers’ past purchases to better target and time emails and other messaging. While the rich data that retailers have at their disposal is enabling new levels of personalization, the marketing may be going in the wrong direction. 

“What we’ve noticed, and what has been true, is that retailers establish the marketing campaign and then find the people to target,” Anil Kaul, CEO and co-founder of analytics company Absolutdata, told Retail Dive. “While what I believe should be happening is to look at the customers you’re trying to reach, literally create a campaign for each customer, and then aggregate that.”

Emails should reflect customers’ past purchases by suggesting likely additional purchases and not the items already bought. And retail data also holds helpful clues about when customers may be more likely to shop at the holidays. So October emails should be going to early birds, while last-minute offers should be going to the procrastinators. 

“You don’t need to send holiday emails to everyone on Dec. 1,” says Kaul. “Based on past history, you can find out which customers plan ahead and which are last-minute. If I have 20% off deals going to customers at the beginning of December, I will have missed the ones who shop at the end of December.”

Mistake: Underestimating Black Friday e-commerce traffic

One of the worst Black Friday blunders of last year was the breakdown of Best Buy’s e-commerce site, which was felled by an unanticipated load from mobile. 

“The fortunate aspect is that it means there’s a lot of activity and buying on the site,” Jeffrey Neuburger, a partner with the law firm Proskauer and an expert on technology, media and advertising-related business transactions including data and security matters, told Retail Dive. “But it’s a problem, and this year I think we’ll see an even higher incidence than last year because of the increase in mobile commerce.”

It’s an expensive problem that can have lasting effects. For each one-second delay in page load time, customer satisfaction calls decrease by 16%, page views by 11%, and conversion rates by 7%, according to Aberdeen Group Research. 

Retailers should dust off their contracts with vendors to be sure the work they have agreed to includes ensuring ample capacity and mobile optimization, Neuburger says. “Run some ‘what if?’ scenarios,” he says. “It may cost some money, but I think that’s a better outcome than experiencing a crash on Black Friday.”

Inadequate capacity can also leave retailers open to cyber-attacks that, as Target saw two years ago at the holidays, can lead to costly, long-lasting problems that hit sales as well as customer loyalty and trust.

Peak times in retail are peak times for theft, even in stores, and that realization should carry over to e-commerce, says Neuburger.

“On the data security point retailers have to be careful,” he says. “In the haste to accommodate the traffic, you don’t want to do anything to make sensitive information vulnerable.  It’s always a consideration.”

Mistake: Underestimating Black Friday brick-and-mortar traffic

Black Friday traffic, of course, is also an issue for brick-and-mortar stores. Wal-Mart in particular has become famous for frightening and even deadly Black Friday incidents in past years that could have been prevented with clearer thinking and better planning.

Those terrible days are mostly behind retailers as lessons have been learned, and as Black Friday sales continue to be spread over more than a day. Still, retailers need a safety plan, with adequate security and crowd control, and insurance that protects retailers and customers when the worst does happen, says Todd Chanon, partner at Dallas-based insurance firm Waldman Brothers. 

Mistake: Misreading Black Friday trends

Improved omnichannel efforts by retailers throughout the year, retailers backing off the sometimes dangerous Black Friday “doorbuster” approach, and increased use of mobile for search and price-comparison by shoppers are just three major reasons why Black Friday is fizzling as retail’s one big day. It's also why many previously tried and true marketing gimmicks fall flat these days. Retailers should be careful about over-promising Black Friday or Cyber Monday deals that aren’t much different than other sales or even their regular prices; shoppers are increasingly onto that. 

The ultimate way to maximize Black Friday could be to minimize its importance to the bottom line, by improving numbers throughout the year, experts have told Retail Dive.

“There’s a way of dispensing with this by doing better in their stores the other 360 days of the year and getting better at selling online,” says retail futurist Doug Stephens, author of "The Retail Revival: Re-Imagining Business for the New Age of Consumerism" and the Retail Prophet blog. “With Prime Day, Amazon said to the entire retail world: ‘We don’t need your Black Friday. We don’t need some archaic tradition of having a sale the day after Thanksgiving.’”