Here a full guide on how to create a Gmail ad in Google Adwords and how to target the audience and how to bid.
Create Gmail ads
Gmail ads are shown at the top of your inbox tabs. Some of these ads are expandable. When you click one of these ads, it may expand into an email-sized ad with videos and images. This expandable format can help you meet different advertising goals. When someone clicks an expandable ad, the following clicks on the expanded content are free.
This article tells you how to create Gmail ads, and set bids for them. It also includes information about how to measure your results in reporting.
Advanced users may want to jump to Create Gmail ads with custom HTML.
