I've always loved playing Mafia. Mostly it is because I loved to make up stories to either defend myself or accuse someone of being a mobster. In class I played the same game, the only difference being that it involved werewolves instead of the mafia. I was the werewolf during the game, and let me tell you about how somewhat complicated the strategy is.
The serious players are always watching your behavior, which includes your body language and speech. They will attempt to signal out somebody who is acting strange. Unfortunately, their thinking is ultimately arbitrary, because people aren't the same. People act differently. You cannot assume a base behavior of people.
The werewolves however have the choice of who to kill. Who you choose to kill can greatly influence who the peasants accuse. When playing as the werewolf, I restrained myself from killing the person who constantly accused me. It may look suspicious. However, do continue to kill those who constantly accuse others. Another thing is know who has information. A friend of mine reasoned that another person cannot be the werewolf due to circumstances, and he was right. So I refrained from killing that certain person until I needed to, like when there is too little people left and my friend could only trust me and not the other two people. Cut your losses, sometimes you want to accuse a fellow werewolf and hang him. When everybody else is doing it and there's no chance of him getting out of it, defending him only shows that you are trying to save a fellow werewolf.