Start with the business problem, not a list of screens. Who will use this, how many times a day, and what does the process look like without it? An experienced team who grasps the purpose often proposes a cheaper route to it; someone handed only a feature list will price exactly what you asked for.
Define what is included as concrete flows: what the user does and what the system does outsourcing versus in house software development response. Equally important, state explicitly what you are not building. A written out-of-scope list removes more friction at delivery time than almost anything else in the document. Mark too which decisions are settled and which is better laravel or .net are still under discussion — honest teams price those differently, and pretending everything is fixed helps nobody.
Write down the hard constraints. The list covers existing systems the software development pricing has to talk to, the data you already hold and its condition, regulatory obligations, user volumes, supported browsers or devices and stacks you cannot change. Where a date is genuinely fixed, say why: an experienced team will often cut the right scope to meet it, but not if the date is a secret.
Write down what completion means for each item. Clear acceptance criteria do not need formal language: a short list stating what must be true when the feature works is sufficient. This single habit shortens the review at the end by a surprising margin and closes off most late-stage disagreement.
Finally, ask for a specific format. Request a task-level breakdown, the assumptions used, the main risks and a range rather than a single figure. Treat a wide range as a signal about the brief: it tells you exactly which requirement is unclear. Then rewrite that part and request a revised number — the revised figure will be the one worth planning around.