Know your audience, Adapt your vocabulary to match your audience, Make client care, Structure your story - Minto’s Pyramid Principle, Demonstrate competence & Establish your credibility Be Specific with a flexible framework in place, Appeal to the head, heart, and hand
I will give you a framework on how to engage clients with minimal effort, it's quite normal that you have to send the 1st proposal to a client with very limited information. The proposal needs to be directionally right and open-ended enough to incorporate new details at a later stage.
Imagine that you are either * The Data Scientist, who is going to implement the solution, will require technical feasibility and complexity assessment like is the right data available? how inference will be integrated with the business process? and is the acceptance criteria achievable with the given data set and constraints?