What should be included in a sponsorship proposal deck?

Be clear with what your expectation is for investment from the partner - are you looking for money, product, or discounted product? Be equally clear on what you're going to deliver. Too often proposals focus entirely on your resume and accomplishments but never include an ask and never explain what you're going to do for the partner. Have a short-term, mid-term goal - a one-year plan, three-year plan, five-year plan with steps to build upon. Make it measurable, not just 'one and done.' At the end of each year, come back with a proof of performance presentation showing how you grew your audience, engagement levels, and any commerce metrics.