I considered the best way to understand a business model, especially after observing how disruptive technologies, like Netflix, displaced incumbents such as Blockbuster. One useful framework for this purpose is the VARS model, which breaks a business down into four key criteria:
V: Value proposition
A: Activities, capabilities, and resources
R: Revenue model (or realized values)
S: Scope of the firm
Here is my analysis on a startup business I have worked on.