I suck at public interactions. Meeting new people, blah. Presentations for the team, dreadful. Questions? No thank you! Even when I have something I'm proud of and need to show it at work for consideration, I'd rather keep the feeling of accomplishment to myself.
If you are reading this, but are thinking, "what a loser", so am I. I have had this trait since a kid. Nobody ever noticed, or made me feel awkward, until I started applying for jobs.
Feelings stronger than any relationship I've been in sabatoged my interactions, making me seem unqualified, unprepared, uninterested and plain stupid.
Overcoming this was not easy. Because this made me feel like I was "defective", the time I wasted trying to understand and overcome my own insecurities wax long, and something I still work on today. But hopefully some of the following advice can make someone else take steps to overcome anything similar without doing it alone.

1. Daily interactions! I hope I'm the only person with this problem, but staying home all the time used to be my routine. But in order to pass interviews, and communicate to teams or clients for work, my habits needed to change. I needed practice. I couldn't count on going to a million interviews and practice, and family/friend practice was fake. Here's what I did. Every day I added time to go to a super market, coffee shop, corner store for a drink. I started asking the cashier how their day was. That's it. This small interaction felt so uplifting. I soon started asking people waiting in line to checkout if they would like to go ahead of me. Now I ask the person behind me if I can pay for their order when I'm at Starbucks. This type of situation usually happens before I went to work, and not only forced me to start the day with having a small conversation, but filled me with a sense of pride and happiness for doing a good deed! (In case you're wondering, YES I have overpaid for some Starbucks orders after asking and finding out it wasn't "just a coffee"... Still did it just to not break the habit...). You don't need to do these exact scenarios, but forcing yourself to leave and interact with one person daily can have awesome results!
   1. Sign up for "Meet-ups" and PRESENT. Meet-ups have groups. But the groups are all there with the same interests. This can make it easier to start conversations because of the chances of everyone enjoying the same topics. If your area doesn't have the type of group you would attend (my area used to have ONE tech-related group...), be brave and pick something else. A big trend I've seen is "MasterMind"/Public Speaking groups. They help people build their skills for talking to audiences. Even if you aren't ready to speak, show up and watch others present. Let the organizer know you aren't ready, but are working on it. If you find a group you like, force yourself to sign up to present or speak. Do it without having any idea of what to talk about. The "act" of signing up will cause a desire to come up with something. When I would tell myself that I would sign up after creating my topic to speak on, I ALWAYS neglected it. Sometimes commitment to the engagement can cause your fear of failure to outweigh your fear of speaking.

It will be tough, or maybe it will make you realize that it was all that was needed to become the badass you always knew you were!

Hope this help!