That's way easier to do when you understand what all the things you're measuring actually mean. The first place I always start when evaluating a business' marketing is figuring out where the heck all their site traffic, leads, and customers come from. But it occurred to me -- if you don't even know what all those channels mean or how they're bucketed as traffic sources to your website -- it's probably pretty hard for you to start that self-evaluation.
The term “organic traffic” is used for referring to the visitors that land on your website as a result of unpaid (“organic”) search results. Organic traffic is the opposite of paid traffic, which defines the visits generated by paid ads. Visitors who are considered organic find your website after using a search engine like Google or Bing, so they are not “referred” by any other website.