Spoiler alert: If you order holiday gifts online, they may come in packages with pictures of the items inside. Meaning, your child or spouse will get an unexpected peek at what will be wrapped later.

Shopping online is one way to beat the brick-and-mortar crowds and save a little cash, but beware: With the perks come problems.

Being prepared for the worst -- or at least covering your bases -- when ordering holiday gifts online can help consumers avoid a host of headaches, said Joe Palko, chief marketing officer for 3dCart Shopping Cart Software, an e-commerce company that provides Web services for 15,000 merchants nationwide.

"A lot can go wrong when you order online," Palko said. "I've seen all the problems."

For instance, Palko recommends contacting online merchants before ordering to inquire about whether shipped packages will be wrapped or otherwise covered.

"In some cases you can type in notes at the online checkout to say something like 'This is a gift, I don't want my son to know,'" Palko said, adding that retailers often call customers who do so to arrange a suitable delivery method.

Keep a close eye on the shipping tracking numbers and delivery schedules so you can plan to be home when a package arrives and avoid the curious eyes of a child. To ensure properly surprising family members, consider shipping gifts to a FedEx or UPS office for pickup later or to a friend's home.

One of the bigger disappointments for online shoppers is having packages arrive late. To dodge this problem, Palko recommends choosing online retailers that publish up-to-date regular and holiday shipping schedules on their websites.

As an example, the Toys 'R' Us website reveals that items sent via standard shipping can take three to eight business days. The toy retailer, like many others, offers faster shipping options in exchange for extra fees. (Be sure to check return policies -- some merchants will accept returns only if you pay the shipping charges.)

To avoid the extra costs while still making sure your package arrives by the holidays, Palko suggests placing online orders by Dec. 10 this year.

"After that, you may have to look into air instead of ground shipping options if you absolutely must have the item on time," he said.