The quotation is a document that has to travel
The most common mistake in business quotations is designing them for the person you have been talking to. That person already understands the proposal. The people who decide often do not, and they will read the document without you in the room, possibly forwarded with a one line message from your contact.
So the first page has one job: allow someone with no context to understand what is being bought, what it costs, when it arrives and what happens next. Detail, specifications and terms belong afterwards. This single change in structure improves quotation conversion more than most changes in pricing or presentation.