To start building up trust between you and her, first try to spend as much time as you can just sitting or laying near her cage (like you were doing when you were on your phone). She will start showing signs that she is getting more comfortable when she explores the room while you are there, or is alert to your presence but doesn’t run or hide, or hops up to you. Once she either starts showing she is comfortable or asks for petting, then you can work on her trusting physical contact.
When she is asking you to pet her she may do things like nudging you with her nose (a nip might follow if her nudges are ignored), sitting very close to you in a relaxed state and not hopping away when you start to pet her, or using her head to nudge your hand. When she uses her head to nudge you for petting, it will be kind of like a nudge towards you and slightly up and she will keep her head in your direction. In contrast, when she uses her head to push your hand away because she doesn’t want to be pet, her head motion won’t follow through towards you and she might turn away. Sorry, it’s hard to explain the difference between the two; when she does the “I want to be pet” head nudge, you’ll know.