After I moved out from my mom's house insecurities are a piece of cake. My confidencev just sky rocketed.
Before, I didn't realise I was insecure, I though I was normal. I just thought that it was common place to be put down and have everything I do contested because it wasn't done the right way. Now I'm married and I won't fall for these shenanigans.
I was insecure about a lot up until about my last year of college. I didn't really overcome anything directly, but I did find a few things I could be proud of. I was able to look at myself and say I had a few things going for me, and so I began to like myself as a person, which I hadn't been able to say before. I still have most of the stuff I'm insecure about but it just doesn't affect me because I focus on the things I'm proud of.
Once you achieve that inner confidence, I believe it will display itself for others too, and you'll feel like less people notice or think about the things you're insecure about.