training birds

[Invigor]

I have a budgie (wanted a cockatiel but couldn't afford one at the time) and the first week or so it would sit on my finger, come out of the cage, no problem. Now about a month later it refuses to do anything.. If I go near the cage it freaks out and goes to the corner of the cage as far away from me as possible.

Any tips to try to tame this crazy bird? I haven't clipped the wings, she came unclipped. does that help? I have to trim her nails soon too, so she's going to need to be handled, but she freaks out and bites whenever I try to get her on my hand...

any ideas?