What the business model canvas is
The canvas (by Alexander Osterwalder) lays out a business on one page across nine blocks: customer segments, value propositions, channels, customer relationships, revenue streams, key resources, key activities, key partnerships, and cost structure.
Where to start
Begin with value propositions and customer segments — the heart of any model — then work outward to how you reach customers, what it costs, and how you earn revenue.
Using it in interviews
The canvas is a quick way to pressure-test a startup or new-product case: if a block is empty or weak, you've found the risk to dig into.