I thought this article was very accurate about what it takes to get a business proposal accepted and could apply to almost any situation where you are trying to get someone's business. The only thing I would disagree with is the idea that you could redo your exterior, floors and kitchen for only $35,000 :)
Also someone in the comments said that this doesn't really apply to a remodel because there would be something tangible to touch and feel from the start, as opposed to a website. I can tell you from experience it would be just as applicable. If it isn't a finished project your client can not envision it regardless of samples and sketches or existing structures. Every project is a proposal whether it is an internal partner or external client and these steps will help you get buy-in and approval.