You can take existing campaigns and clone them to create new campaigns. The cloning process will duplicate the entire campaign and you can then change any attributes that are different.
You will need to start by clicking through on the Campaign you wish to clone.
In the upper right corner of the campaign, click on the More menu and select Clone campaign
You can change the Advertiser, Campaign Name, Budget, and Flight Dates.
Press Clone to complete the process.
Other modifications can be made from directly within the campaign.