If you miss any of the above mentioned, she dies.

At the end of the Horizon, use Paragon/Renegade option while talking to her father.

Meet her on the Citadel later, and when asked for Alliance resources for some operation, give them to her.

Talk to Miranda through Spectre terminal on Citadel, and warn her about Kai Leng (make sure she responds with 'I will make myself ready' or something).

Read Kai Leng dossier on your (or Shadow Brokers, not sure wich) terminal after you encounter him before talking to MIranda again.

Talk to her nicely and ask how you might help.

Meet her at the Docs in the Citadel BEFORE Cerebrus attack on the Citadel.

It is also rumored that you can break up with her in the hotel room (meeting 3) but you cant do that during first meeting - this will kill her definitely. edit It is reported that you can break up with her in ME2, just not in ME3.

If you romanced her at any point, do not break up with her.

Make her survive Suicidal Mission (obviously).

edit It is reported that you do not have to make her fully loyal, but you must complete her loyality mission. Here are the things you have to do to make her live in the end of Horizon Sanctuary mission: Also check the bottom of the post for some PlotID bool values to use with Gibbed save editor for those who are desperate. I spent around 5 hours spread in 4-5 days to make this work, and i hope this info might help someone who got cought desperately as i did More on that later.

Can you save miranda in mass effect 3