Forrester forecasts $78.7 billion in US online sales this holiday season (including mobile and tablet sales), projecting double-digit growth rates for the third year in a row with a 15% increase over 2012’s $68.4 billion in sales. This year, 167 million shoppers will go to the Web to do their holiday shopping, spending an average of $472 for the season. “Strong economic growth and low unemployment rates project a healthy playing field for online holiday sales and outweigh any lingering dampening effect of the government shutdown,” writes Analyst Sucharita Mulpuru in the new research report out today.

Despite increased consumer spend, online retailers can’t expect to see double-digit growth numbers without adhering to holiday retail best practices, notes Mulpuru. Retailers must take note of consumer expectations: In a recent Forrester survey of US online adults, 50% said they would consider buying from an online retailer that they had never bought from before if it offered the lowest shipping cost or free shipping, while 42% said the best deal offers would sway this decision. “But with consumers now expecting them, discounts alone won’t be enough to guarantee the results that retailers are looking for,” writes Mulpuru. As such, the most successful online retailers this holiday season will be those that use mobile to their advantage, capitalize on email lists to attract repeat shoppers, and, above all else, ensure that execution is flawless.

To learn more about this research, visit the eBusiness & Channel Strategy blog here.