Speaking as somebody who generally plays a lead BD role vs. programming (but I'm assuming this question is a level higher than programming, with project being a startup).
1) Ask why people would use it (problem)
2) Figure out who would buy it (exact names, contacts)
3) Rough Wireframes, 5 slide pitch deck
4) That's all I need to meet with customers and get orders. I won't move forward until orders are secured and signed.
Are you saying that you won't move forward with any development - not even a prototype - until you have paying customers? And what does it mean to have a "secured and signed" order? Does it mean that they're about to cut you a first check as an advance on purchasing / subscribing to the product?
Have you always practiced this, or did it take some realization?
The furthest I will generally go is black and white mockups in Balsamiq. If the backend is a little more complex, we may begin planning schemas and algorithms, but rarely much further than this.
By secured and signed, I do mean a signed order for a license, to be delivered at a future date, generally with a discount or longer term to compensate for my clients risk. The delivery date, scope, seats, license term and cheque cutting dates are always pre-defined. Quite often, I'll extend a discount for a downpayment so that the company has some instant cashflow.
I didn't practice this in my first startup, but have since. It's not easy, but always worthwhile in the end, and helps accelerate through that awkward early growth stage, and means while development is going on, I can pitch us with a legitimate client backing.
To clarify: I am almost exclusively in B2B software.
1) Ask why people would use it (problem)
2) Figure out who would buy it (exact names, contacts)
3) Rough Wireframes, 5 slide pitch deck
4) That's all I need to meet with customers and get orders. I won't move forward until orders are secured and signed.