There are several things to consider when buying or selling a business. The most important is to listen to the other side. There are always reasons why someone wants something - even if you don't agree at first. Find out where the other side is coming from, then make a decision on whether you can live with it or not.
Next, whether you are the buyer or the seller, you can not have everything your way. You can't win on every point or issue. Be prepared to give in on those areas that are not as important as those you feel most strongly about. If you are a seller, you may not be able to get a real high price and a real high down payment. You will have to decide which is more important. The same is true for the buyer. You can't have it both ways.
Always enter the purchase or sale of a business with a spirit of cooperation rather than one of confrontation. The buyer or the seller, as the case may be, is not the enemy. If the seller wasn't interested in selling, the business would not be for sale. If the buyer did not like the business there would be no negotiation or eventual sale.
The secret of a successful negotiation is laying out all the points on the table for discussion. It is key to understand where everyone is coming from and to understand what is and what is not important to each party. When there is a sense of cooperation among all of the players, a successful deal will usually result.