What is the difference between a sponsorship deck and a proposal, and when should each be used?

A deck is eye-catching marketing material used to attract initial attention and start a conversation with potential sponsors - it can be a postcard, video, website link, PDF, or pamphlet with lots of imagery showing what a brand could get involved with. You send decks when first meeting someone to 'fish' for interest. A proposal is a detailed Word document created AFTER you've established a relationship and learned what the sponsor needs. It lists specifically what you will deliver and what you expect in return. Never send a proposal to someone you just met - you don't propose to someone on a first date. The proposal becomes part of your contract and what sponsors will hold you accountable to.