A winning proposal contains all the relevant information that client is looking for under appropriate heads.
Proposals, if not in proper shape and with complete content, is of no use to the client. One of the most prominent reason behind rejection of any proposal is its presentation. Client looks majorly for Solution & Proposed cost in a proposal. A top level table of content should be more or less similar to this:
This is a high level design for any proposal. Detailed proposal data would be covered further.