itzjbean gave really good advice. I would also say it also sounds like she's under-stimulated. Before I sit down for a long time next to my blue and gold, I always give her about 20-30 minutes of one on one play time. I'll take a water bottle and let her throw it a bunch, or a big piece of cardboard, which we'll pull back and forth and she'll shred. I'll even use manzanita branches, which she chews into sawdust. Wood seems to be great for their big beaks, and in my short experience, it also wears them out. When she starts being less enthusiastic, that's usually when I stop playing with her.
I tied a foraging toy onto the perch I usually put Sunny on, and I put a second soft wood perch above the bottom one, so now she can spend hours shredding the wood dowel above her. Basically, she always has something to do that she likes. This also makes her easier to handle and less beaky because she has already spent an hour or two chewing on the dowel before I pick her up to play with her again, or have her on my arm. Something like this might be really good for Jewel. I'm not sure what she likes toy wise, but if she does like wood, it will keep them entertained the longest which means they get more worn out.
With the biting, I would say read all of the Birdman666 posts. They're really helpful. They are actually what helped me get Sunny to the point she is now, where she almost never bites. Because Jewel is young, some of it won't apply to her (since she's not aggressively biting), but there are still a lot of different techniques that might be more effective than what you're using now. One of the things in the Birdman666 biting posts, was using your hand in kind of a half fist, then pushing your palm into the bird's beak when they lunge. I've found this extremely effective in stopping the behavior before she gets wound up and actually bites. It's like saying "stop that!", and with Sunny she always pauses and looks at me. After that she stops lunging.
I'm sure some other people will chime in. Try the search function too. There's a ton of information here, and it's been filtered through hundreds of bird lovers and people who have become more or less experts on handling parrots, so you only get the good, effective information. I was having trouble with reading different things different places on the internet, and I'm new to larger parrots, so it was hard to tell what was true and what wasn't. I found all the techniques and information I've needed here, and it's all helped me in helping Sunny and understanding her better.
