The best way to win easy fights is to find a weak player and attack them over and over. However, even better, is to find an inactive weak player. Many people quit playing mafia wars but leave their accounts active. If you attack an inactive player, you don't have to worry about being put on the hitlist or being attacked by higher level friends of the person you are attacking.
How to spot an inactive player:
Inactive players tend to be low in level, have small mafias, and have old collectibles. The only way to know for sure is to attack the person and look at the report of the fight. Here is an example of a fight with an inactive player(click picture to see it):
Now that you've spotted this inactive easy target, you need to bookmark their profile. Simply bookmarking the attack page will not work - you have to open their profile in a new window, then bookmark the new page. Here is a step-by-step guide with pictures to clear things up:
1. Once you find your weak inactive target, open their profile in a new tab or window(by right clicking his name), like so:
2. Bookmark the new tab or window that opens up (ctrl + d on most computers). Now instead of attacking random players off of the attack list and hoping you win, you have access to this weak inactive player all the time, right in your favorites list!
3. You can even save time by bookmarking the "attack" link, so that you can simply click your bookmark and attack the inactive player. The advantage here is that you can hit your refresh button (F5 on most computers) times to spend all your stamina attacking the same weak target. This works well with the leveling guide.
4. Profit! Easy wins without retribution.. after all, why would an inactive player care if you attacked them all the time?