Google posted what it considers to be best practices for managing mobile campaigns, and some specific instructions for using DoubleClick Search to do so, on its DoubleClick Advertiser blog.

Google says to create separate campaigns for each platform you’re targeting, write specific ad texts for different device operating systems, bid differently (sometimes you may need to target higher positions to get traffic because of fewer ad slots per page), direct users to a mobile-optimized landing page, tailor your keyword list to the mobile searcher, and bridge online and offline.

“Mobile click-to-call campaigns can be powerful lead generators,” the DoubleClick Search team says to that last point. “When setting up a click-to-call campaign, consult with your DoubleClick Search Technical Account Manager to learn how DS3 can import data from your advertisers’ call tracking solution to allow optimization on both online and offline conversions.”

Some of the points are more obvious than others. Having a mobile-optimized landing page is perhaps the most important of them all, and is a big reason why Google has been pushing that GoMo campaign, encouraging sites to be optimized for the mobile experience. Do you expect many conversions if someone clicks your ad and it looks like crap?

Google makes a good point about targeting keywords to mobile searchers.

“It’s still a good idea to copy the keywords from your desktop campaigns as a starting point,” the team says. “However, mobile searches still tend to contain fewer terms than desktop, so it’s likely long-tail keywords that receive traffic on the desktop will be less effective in smartphone campaigns and may even bring down your quality score. Also, many mobile searches (over 20%) contain geomodifiers; be sure you’re including those city and region names in your keywords for stronger matches.”

Emphasis added.