The goal of the negotiations should be to maximize the objectives of both parties, not to see who can beat the other side. A starting point for negotiations can be a draft contract, but just because there is a written draft does not mean that the draft cannot be changed. Word processors are wonderful things and change is mechanically easy to do. The greatest point of conflict probably will be price. Concentrate on the problem of maximizing objectives and not on personality conflicts.
Social skills devoted to avoiding personality conflicts are important skills in negotiations.
If there is an important term, put it in writing. As part of the sales process you as the Seller will have to provide the Buyer with certain state and possibly federal disclosures. Most individuals who purchase homes finance their purchase. In practice the risk of a Buyer not qualifying for a loan is one of the largest risks that a Seller has. It is traditional and appropriate that any deposit be held by a third party escrow agent.