few suggestions for monopoly beginners:

– in the start buy every property you land on

– as soon as you need money mortgage properties which do not have houses

– properties which do not have houses are not very useful

– do not buy railroad, electricity and water

– cheapest properties can pay of very well with hotels which cost only 5.000

– do not worry to about building the 4th house if with already with 3 houses you can get 10.000+

– while negotiating propose solutions which you yourself would accept

– if you are the dominant player, try to make the game fun for others

– negotiation prices are based on each situation, there are no universal rules for negotiation

– monopoly is more of a chance than strategy game

– teach less experienced players than you

– learn from more experienced players, ask them to explain their style

– have fun!