It's a question I get everyday: "I'm afraid to sing in front of people! How can I become a better singer?" There are many options but one of my biggest is easier said than done: Sing for other people.
I know, probably not the answer you wanted to hear. But there is something very special about putting yourself out there and getting feedback. You might be told you are a flat, that you had a weird trembling in your body- but this will go away once you are aware of it. Get a mirror and fix the shake. Get a voice coach and fix the pitch. Let it all roll off your back and listen to the constructive feedback. I especially think it's important as singer we learn to develop a thick skin because it will never get easier. I have one video on Tik Tok with over 4 million views and the trolling is astronomical haha! I'm a seasoned performer and know to let it roll off my back and this is something we must all learn to do.
So if you want to improve; but yourself out there. You will never win a basketball game by only playing til the second quarter. Keep going and you will find the improvement follows with every performance.