Creating a good estimate is a time consuming process. We consult on scores of projects every year, issue a lot of free estimates, and try to create a proposal that is complete and also responsive to client and project.
Our estimates are line item based, we think of them as similar to a menu at a restaurant. We outline the scope in terms of a wide array of options and detailing, and then refine the estimate depending on budget and client needs. We find line item estimates work better than lump sum estimates, especially at an initial phase. They take into account elements like a patio that may have a range of potential sizes depending on design, say 400-750 sq.ft., and a range of potential materials- like concrete, pavers, or flagstone. Line item estimates also allow for prioritization and the division of work into phases as needed.
Here is an example of an a recent estimate in San Anselmo that shows the type of granular detail involved:
An estimate like this one takes a lot of time to put together with such fine level detail. There are 5 work divisons and 26 individual elements. However, when we are starting out without any design documents, it serves as a great project roadmap to further develop the project.