Last year, I wrote about my handy "Getting Started with Revit API" document (sometime I called it "phase zero") as I get inquiries about Revit API every so often. Here it is the updated version: Download Getting Started with Revit 2014 API. The changes are very minor: version number update and pointing to newer recordings. Old recordings may be still valuable for learning basics as the newer ones tend to focus on more advanced and specific topics. So I'm not going to repeat it here; rather I refer to the last year's page for the majority of part.
Another inquiry I received recently is about learning materials about Family creation. I double-checked the content manager here and he confirms that the Family Guide posted here is still the most complete one you can refer to (although it was not updated for a few years.) This page include guides translated in various languages, such as Chinese, German, French, and Japanese. If you are new to Revit, this will be a good starting point to learn Family creation. If you are coming from Programing background, I must also emphasize that to master Revit API, you will need to understand how Revit works in UI.