Before I traveled to see the boat I bought, I made a list of questions. I sent the questions to my buyer-broker who sent them to the listing-broker who sent them on to the seller.
Most of the questions were clearing up discrepencies on the listing sheet (i.e. listing said AC and engine-driven refrigeration
-- elsewhere said 24VDC refrigeration
. clarify?) or whether the vessel was US duty paid.
When I went to see the boat, I stayed for two full days and went over everything on the boat thoroughly. From this I developed another set of questions. Same process.
Then I went over the comparables with the buyer-broker. I did my analysis on comparables with the buyer-broker. We turned that into a rationale for the offer and start of negotiations.