Endings Guide (spoilers)

Spoilers ahead! Try playing the game at least once before viewing. 

For the best player experience,  interrogate each suspect character and learn more about them! This gives you the chance to know as much as you can about the characters individually and gain insight about others.

Bound end: 

• Do get on the Toreador's good side. Obey and don't question or fight him back. 
• Do make the Malkavian dislike you. Go for dialogue options such as entering without announcing yourself, calling the situation a "scheme", avoiding his question, etc. You can also be unkind to her before you meet him. 
• Don't take the phone.
• Do accuse the Ventrue.

Diablerie end: 

• Do choose to obey or disobey the Toreador.
• Do not make the Malkavian like you. Try the dialogue options such as entering without announcing yourself, avoiding his question, etc. Remember your opportunity with the Brujah as well to avoid earning as many points with the Malkavian. 
• Do either take or leave the phone.
• Accuse the Brujah or the Malkavian 

True end (original): 

• Don't get on the Toreador's good side.  For example, choose to investigate instead of staying, or say "yes" to threaten instead of "yes" to accept. Disobey and resist him as much as you can.
• Do make the Malkavian like you! You have two opportunities to do this before reaching your end. First, be firm but kind to the Brujah. Second, choose dialogue options like, announcing yourself, agreeing the situation is an "elaborate joke", reprimanding him for his question, and agreeing with the Brujah's cause.
• Do take the phone.
• Do accuse the Ventrue.

True end (alternative)

• Follow the same instructions for the true end, but choose "Stay" instead of "Run".