Start out by completing missions that have a high payout with a low energy cost. These missions will help you gain money faster in Mafia Wars because you will be able to complete more missions faster and gain more money.
Buy Property. Buying property in Mafia Wars on Facebook will allow you to gain money every so often. The more property you own, the more money you will get. Every time you log into Mafia Wars, complete all of the missions that you can and then spend all of your money on property. Make sure that you keep all of your property repaired every time you log into Mafia Wars because people can rob your property and it will lower the amount of money you gain.
Rob other Mafias. Click on the fight button and then click on Robbing. This will allow you to rob other Mafia’s property and gain a good amount of money. Each time you rob another Mafia it will take 1 stamina point. Try to rob Mafias with low amounts of members and close to the same level as you so that you have a better chance of successfully robbing the other Mafia.
Ask your Mafia Wars friends to promote you to their Safecracker or Bagman. These are Top Mafia spots that will allow you to occasionally gain extra money doing jobs and fighting other Mafias. The more people you get to promote you, the more chances you will have to gain extra money while doing jobs and fighting other Mafias in Mafia Wars on Facebook.