There are miles of books on self-development shelves telling people how to improve themselves, overcome problems and generally become more perfect or more satisfied (or both). We really, really want to know the secret: that one thing that would make the difference and allow us to magically get what we want and then like it when we get it.
Or do you? Do you want it enough to take a really simple action, over and over, that I guarantee will change how you feel and how you perform? Yes. This is a dare.
Here is the action. Whenever you become aware of not liking something about yourself or your performance, think of someone you actually know who has a quality you would like better. Don't analyze; don't mimic; don't beg them for their secrets. Just think about that one person and your actual interactions with her/him when s/he was demonstrating that quality.
As you focus all your attention on that person who has the quality and can do that thing, be curious about all of that person: how they stand and breathe and move and their expressions and the sound of their voice. Gather all the information you have stored about that person having that quality. Then let it go.
And go on with your day.
If you require scientific precision, write down the problem before you start and set an alarm so you can check in with the problem one hour and several hours and one day later. When you do, just be curious. At first you might think nothing is different, but something is always different. Find out what it is.