Have the passport of every traveller in front of you before you ask for a price. The photo page is enough for a quote. Six months of validity is the usual minimum, and some visas ask for more.
Decide the room split first. A family of five is not always a quad plus an extra bed. Hotels differ, and the price changes with the split.
Ask which parts are still tentative: the hotel name, the airline, and the visa fee. Pay a deposit only against a written note that lists those three.