The only way for you to see which advertising media are actually returning your investment is to use Google Analytics link tagging. It’s an extremely simple process once you’re prepared with the basic knowledge on how to categorize your various campaigns.
First, understand that you only tag what you need to tag. Don’t confuse yourself, or add unnecessary work. For example, if you need to track a Google AdWords account that is linked with your Google Analytics account, you don’t need to tag your AdWords URLs at all. Google Analytics does it automatically. Other paid marketing campaigns like banners, and unpaid media like email campaigns should definitely be tagged.