Online shoppers spent over $42 billion last year in November and December, a 14% increase over 2011. Undoubtedly, the next month and a half will represent the busiest and most profitable period for online retailers. To capitalize on this growing revenue opportunity, advertisers must identify the most critical days throughout the 2013 holiday season and prepare their campaigns in advance. To help, Marin released the annual search marketers’ guide to holiday preparedness last week, highlighting the key dates for retailers to mark on their campaign calendar and providing best practices for a successful holiday season. The key dates are summarized below:

Early Shopping – November, with the help of Thanksgiving and Black Friday, will continue to represent a critical time period for retailers to engage and convert shoppers turning out early for “site-busting” deals and promotions.

Thanksgiving Day (Nov. 28) – Thanksgiving drove one of the five biggest days during the 2012 holiday season in terms of search volume with spend increasing 59% and CPC increasing 22% compared to 2011.

Black Friday (Nov. 29) – Search interest was at its highest on Black Friday 2012. Expect Black Friday to continue driving a significant share of clicks and revenue during this holiday season.

Cyber Monday (Dec. 2) – Cyber Monday continues to drive significant click volume with impressive revenue per click (RPC). Undoubtedly, Cyber Monday will represent a significant share of online revenue for retailers this year.

December Sundays – In 2012, and similarly in 2011, retail search interest peaked on Sundays. The only exception was the Saturday before Christmas, which saw more search activity than Sunday.

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Now that you have a general understanding of the key dates, be sure to set up your holiday campaigns and ad creative in advance. That means aligning your promotional calendar with keywords and ad creative, and avoiding editorial review by pushing out campaigns prior to launch. Once the holiday season begins, you won’t have much time. For additional best practices on holiday preparedness, read The Search Marketers’ 10-Minute Optimization Guide for the Holidays.