First determine if her screeching is merely attention seeking, or if it's possibly due to something that may be bothering her. See if you can find a pattern to her noisy times. Who's around, what's going on, what time is it, etc. Look at her overall schedule--mealtimes, bedtime, playtime--to see if there are any adjustments that could be made. For example, if she's not getting enough physical exercise or mental stimulation, she may be bored and restless. Another example: If she's not getting enough quality sleep she may be cranky, especially in the evenings.
Finding a pattern and making any adjustments that could be made may help you have more control over the situation. Often if you can predict what's going to set your bird off, you can prevent outbursts.
Without more information to go on, I can't offer much in the way of WHY she may be too noisy, and finding out the "why" is important for me to really help you with the problem. However, I can tell you that for attention-getting screaming, the best thing to do is respond to her when she's being quiet, NOT when she's noisy. Often it's helpful to actually leave the room, taking away any chance that she could receive reinforcement for her noises. As soon as she quiets down, then come back in and pay attention to her. The basic idea is to ignore the behaviors you don't want, and respond to those you do want. If leaving the room isn't possible, then everyone must do their absolute best to not look at her, talk to her, scold her, etc. because the idea is to withhold
any reinforcement for unacceptable behavior. In order for this to work, you have to be consistant and everyone in the home has to be on the same page in terms of how they respond to the bird. If one person loses it and yells at her, that will slow down the training success.
I find that most parrots also will benefit from more active out time where they have something to actually do vs. just sitting on a playgym out of their cage. Teach her some tricks and games, dance with her, whatever. My website,
www.kimbear.com , has a link to a good series of trick-training products that are fun for both people and parrots. The overall idea is to keep her active and engaged in something fun that will help her use up some energy. Even a good bath helps. Parrots are often quiet after a bath because they have to spend some time grooming after being wet.