Patience! That's the best advise I can give. Start out slowly. I had a hamster like that, and this is how I tamed her:
First, just sit in front of the cage and watch her. She'll probably hide or something, but after several nights, she'll ignore you there and do around her usual bussiness. When she's ok with your presence, put her hand in the cage, far from her, and leave it there. Mine used to roll into her back and show me her claws and teeth when I opened the cage. So I put my hand on the cage floor as far from her as possible. After about a week of this, she stopped rolling on her back. When this happened, I started moving my hand near to her, with a treat. I put my hand fully opened, palm up. Many people start putting the hand palm down, as this posses less of a threat to the hamster, so you can try that too. After some time of the "treat in palm" thing, she started going to take the treat, usually running with it to eat it at a safe place. I kept my hand in there while she ate it, sometimes putting in a new treat. With time, she started eating the treat in my hand, and after that, I started lifting my hand with her on it. It took me 3-4 months, but I managed to get her tame enough to take out of her cage and play with her.
Remember, lots of patience with little Arabella and good luck!