Nicolò Falcone is the world championship of Monopoly. Whenever my kids want to play Monopoly, I attempt to dissuade them because the game bores the pants off me and it takes forever. But to each his own, I guess, so long as I get to be the shoe. Here's Falcone writing in The Guardian:
People ask for tips and I tell them to buy three houses on each property when you own a complete set. Also, jail is your enemy at the beginning of the game, but your best friend towards the end. By then, if you go to jail, stay there for as long as possible because you can collect money off your properties but you don't go around the board paying other players. There are also Monopoly "heat maps", which show the places that are landed on the most.
Also, read the rules. Knowing them properly will help you win. For example, you can buy and build houses any time between other people's turns, not only when it's your turn. While Monopoly can take hours to finish, the game that got me my world title was over in 47 minutes. That is not because I am the Maradona of Monopoly but because I know the rules. It shouldn't be a five-hour game.