The best way to avoid losing fights in Mafia Wars is to not get attacked in the first place. The same tips that I covered earlier in the "How Not to Get Robbed" section will also help prevent you from being attacked. However, if you like to fight other players, it is inevitable that at some point you will encounter another player who will either put you on the hitlist or get his buddies to attack you. In this situation, there are a couple things you can do to boost your defense:
1. Recruit more Mafia Members
It's a bit of a redundant theme at this point, but one of the easiest things you can do to not lose as many fights on defense is to add mafia members. If you are lacking mafia members, look for groups on facebook like "Mafia Wars Recruitment Center" and you will be able to find more mafia members there.
2. Equip your Mafia
Now that you've added more mafia members (or already had 500), it's important that they are fully equipped. You will want one weapon, armor, and vehicle for each person in your mafia. The higher the defense on the items, the better off you will be when defending yourself from attacks. See the best of list for up to date information on the best weapons, armors, and vehicles.
3. Put points in Defense
Even if you have a full Mafia with all the best equipment, if you have no points in defense, you will still lose fights to high-end players. One easy way to get points is to do the collections; several of these, such as the ties and rings, will add a good bit of defense to your stats. One point in defense for every level you have will set you up to be above-average when it comes to getting attacked. Additionally, use your godfather points from leveling up for stats, and put those in defense if you feel like you are still getting killed too easily.
By filling up your mafia, collecting the best defensive weapons, armor, and vehicles, and by putting some points in defense, you can be sure to cut down on your losses in the future!