* Defense and Attack Points - To successfully fend off attacks and win fights, according to people in the Mafia Wars forum, your defense and attack points should be at least double the level number you are at. So, for example, if you are at level 10 then your attack and defense points should be at least 20 each or more.
* Robbing - Without getting too analytical I only rob people who have fewer mafia than I do. If I successfully rob someone then I continue robbing them until my stamina runs out. When robbing properties I try to find people who also have more than 30 of each kind of property. Sometimes you find someone who has over 100 Mega Casinos. If you rob them successfully they sustain only around 1.5% damage each time which means more opportunity to rob them until they sustain 70% damage.
* Right-click everything - This has to be the most important tip of all. If you've ever clicked the back button in your browser while playing Mafia Wars you know you'll be taken away from the game and end up at your Facebook page. When that happens it is almost impossible to get back to the same Mafia Wars page you were at before. So to navigate to the different pages without losing your place you should right-click your mouse to go to the different pages. When your health is below 20 you right-click "go to hospital" and replenish your health in another window and then go back and continue robbing someone. Right-click "go to bank" to deposit money and then return to your original window. Remember to bank your money before robbing someone new as you may lose some if they are stronger than you.
With these 3 strategies you'll be playing Mafia Wars like a pro and enjoy the game more. And remember to always bank your money so people can't rob you. I hope you have fun.
You can find more Mafia Wars strategies at my blog. I also recruit members for my mafia family at http://mafiawarsrecruitingcenter.blogspot.com.