Hi there! When she bites you too hard on the ear (or anywhere) react like a bird that got hurt. Screech like you're in pain. That's a good way to communicate to her that she hurt you. Stay consistent, it may or may not take a while but she'll get the idea. Avoid reacting in a human way, which can sometimes be out of anger (not saying you get this way but I have a few times in the past, until I learned the proper way).
If she keeps doing it, then restrict access to your shoulders for now. No bites mean less chances for an unwanted habit to form.
If she crosses the line again and again with her biting, just gently set her down on a perch, calmly walk away and close the door behind you so she doesn't follow. Re-enter the room in 15 to 45 mins, no longer. This is called shunning. Separation from you is a consequence for hurting you. Mind that it works only for parrots bonded to you or fond of you on some level (they must like you to feel the sting of your absence). Also make sure that the room you're leaving her in is bird-safe. No open doors, windows, glass/mirrors to crash into, electric fans, other pets to pounce on him etc.
Good luck! Stay strong and scritches to your little one.