In addition to what @eleni said about her bird's wings being clipped: Her bird came to her clipped, and she was able to train Stella while clipped. However, my Ollie came to me as "the most grumpy and difficult of the clutch" according to the breeder, yet he was fully flighted and is the most tame little bird I have ever dealt with. He's such a momma's boy and only took a week or so of "training" to become tame.
When I "trained" Ollie it wasn't really training at all. At that point I had never had a parrotlet; although I had had a Sun Conure, Parakeets, and Lovebirds. He was training me if anything. I was always under the assumption it'd be impossibly to tame a flighted bird, and some people remain under than impression. Ollie changed that for me. I literally let him take interest in me. He'd never get millet (aside from the car ride home, and his first day) unless he was joining me. So he started to equate me to "well she gave me millet, can't be too bad". Eventually the bond formed, and now he's a little blue tumor (as some people would call it).
EVERY bird is different. Find what he/she likes and train them with it. The first couple weeks for Ollie it was millet. After that, Ollie enjoyed my company so much the thing I used for his "taming" was me! He became very beaky so every time he'd nip my neck I'd say "No" firmly, and then remove him from my shoulder and place him gently on the floor. He was flighted, so he could fly back up, but eventually he just stopped nipping.
When I "trained" Ollie it wasn't really training at all. At that point I had never had a parrotlet; although I had had a Sun Conure, Parakeets, and Lovebirds. He was training me if anything. I was always under the assumption it'd be impossibly to tame a flighted bird, and some people remain under than impression. Ollie changed that for me. I literally let him take interest in me. He'd never get millet (aside from the car ride home, and his first day) unless he was joining me. So he started to equate me to "well she gave me millet, can't be too bad". Eventually the bond formed, and now he's a little blue tumor (as some people would call it).
EVERY bird is different. Find what he/she likes and train them with it. The first couple weeks for Ollie it was millet. After that, Ollie enjoyed my company so much the thing I used for his "taming" was me! He became very beaky so every time he'd nip my neck I'd say "No" firmly, and then remove him from my shoulder and place him gently on the floor. He was flighted, so he could fly back up, but eventually he just stopped nipping.