Since people fail at Mafia, and I have won as Mafia millions of times, I decide to do this. ^^
Godfather[]
As a Godfather, your two goals is to give orders to Mafioso and kill everyone in town. If you don't give Mafioso orders, the Mafioso may have the option to kill you.
It's best to hold out and not kill until someone reveals their role to Town. Yet again, you have to be active, and, if there's no kills within three or more days, the game ends.
-If the Mayor reveals himself/herself early in the game (which might not be likely, but it happens), it's best to make quick waste of him/her.
-Remember, Mafioso has the ability to kill, and if you don't give orders to him/her, you will have the probability of getting killed (if possible. I tend to tell my Mafioso they can kill whoever they wish to).
-If there's a Consigilere and they have investigated someone last night, ask what role the person they investigated is. If they found a valuable role, kill that person Consigilere found out immediately.
-I tend to make an alliance with someone that's not in Mafia, and then kill them in a later night. It may be heavy betrayal, but it's fun for someone like me (also known as a psycopath who wants everyone to die, also known as Serial Killer).
Mafioso[]
As Mafioso, your two goals is to vote on who to kill in the Town and follow Godfather's orders. You shall vote on someone and kill them that night.
It's best to follow Godfather's orders by all means necessary. If someone reveals their role to the Town, then kill them.
-If the Mayor reveals himself/herself early in the game (which might not be likely, but it happens), it's best to make quick waste of him/her.
-Remember, Godfather has the ability to kill and carry out orders. If he/she doesn't give out orders, you can kill him/her, but that would mean taking out someone that will help you win and kill all Town members.
-If Godfather tells you to kill whoever you wish to kill, it's best to start with you being inactive. After a couple of days, someone will reveal their role, and you can kill them--whether or not it's important.
Consigilere[]
As a Consigilere, your goal is to investigate anybody out of Mafia. You can immediately determine their role, as Investigator (Town) is given three or two options about what their role may be.
It's best to investigate everyone by all means necessary. If you learn their role (i.e #1 is Mayor), it's best to reveal it to Godfather or Mafioso, and they can take care of the rest.
-Investigate people who seem kind of suspicious in Mafio's book. If their role is a Killing role, it's best to back up away from them and tell Mafioso or Godfather.
-Don't seem suspicious to Town, you might get killed way too early for your good. You have to stay alive with the rest of Mafia.
Janitor[]
As a Janitor, your goal is to clean a person's role--meaning their Last Will will be completely erased, and their role cannot be determined by other people.
It's best to depart from Disguiser's plans, and take your own way. If someone reveals they are Mayor or Sheriff or Investigator, it's best to clean them as Godfather or Mafioso takes care of the killing.
-You only have three times to cleanse a person's role and Last Will.
-For example; let's say the Medium revealed their identity to the town early, and Godfather is going to kill him/her. You can cleanse their identity so that the Town thinks the Medium might have been Serial Killer or a Killing role.
-It's good to clean the Investigator and the Spy.
Disguiser[]
As a Disguiser, your goal is to act as someone the next day and inhabit in their body (if they die)--meaning your original will die, you will be the character you chose to be, and roles will be immediately switched (i.e the character you chose is Witch, and you are Disguiser, so the character you are the next day is Disguiser and your main character is Witch).
It's best to depart from Janitor's plans, and take your own way. If someone reveals they are a Killing Role, it's best to disguise as them (as long as Godfather or Mafioso agrees to take them out).
-You only have three times to disguise as someone, so disguising as an important role may be necessary in survival.
-Let's say someone revealed that they are Mayor. The following night, beg Mafioso or Godfather to kill them (but keep in mind that there might be a Spy) so you can disguise as them. They'll kill the Mayor, so you can successfully disguise as them (if there isn't a Bodyguard with the Mayor). If you succeed, then you will be them, but your original character will die, and the game will say that your original character's role is Mayor.