Don't be a jerk.
Can you be someone people don't mind losing to?
Monopoly™ is a zero-sum game; you can't win unless everyone else loses; indeed, everyone else must usually be wiped out completely. As such, many players perceive the stakes as higher in Monopoly™ than in most other games. Also, you will likely be playing against people you know; perhaps people you know very well or even family members. There may be more on the table than meets the eye.
The fact that negotiation is such an important part of the game means that how people feel about you personally will likely have a strong influence on your success in the game. Every negotiation is a sales exercise, including those in Monopoly™. If people feel negatively about you, selling them, that is, getting some kind of deal, may be difficult or impossible.
The challenge may be to be assertive without being aggressive. Arrogance, insults and being inconsiderate, as much fun as they may be, will not help you. Trash talk can kill a deal. In particular, you want to avoid behavior that may cause others to align against you. The urge to create alliances in Monopoly™ is strong; your efforts must be to create alliances in your favor. Diplomacy and grace will serve you well in Monopoly™ and in life.
Every deal is an act of cooperation. If you don't know how to at least feign cooperation, you will likely lose the game. It is this tension between cooperation and eventual destruction that appeals to some players.
