Anchor the proposal to their priority
Restate the business outcome in the recipient's language and reference the date sent. Do not resend a long pitch without identifying what may still block a decision.
Offer a low-friction next step
Ask one decision question, propose two short meeting times, or offer a revised scope if budget or timing changed. Include the proposal link so nobody has to search for it.
Use a respectful close-the-loop note
After measured follow-ups, say when you will archive the opportunity unless priorities change. This creates clarity without inventing pressure or a false deadline.