Do you know if your african ringneck is wild caught or captive bred?
The easiest way to start working with your ARN is to first figure out what her comfort zone is. That is, at what point is she comfortable with you standing near the cage? And at what point does she go "on edge" looking for an escape? If you can figure out where this line is, you can stand there looking indirectly at her (don't stare at her full on!).
Well, more specifically, walk towards her cage, if she goes on edge, take two steps back. Wait a few seconds or minutes. Try to approach the cage again. If her behavior indicates she's looking for an escape, take two steps back. You can try repeating this until she gets comfortable with you being near.
Or another approach... find out her favorite foods, place these inside the cage, then step back to her comfort zone and allow her to eat in peace. Repeat. Repeat again but being a little closer.
Over time with her getting more comfortable with you, you may then be able to graduate to feeding her treats by hand.