How can I overcome being socially awkward?

I’m always either at work or my apprenticeship, the people that I did consider friends act like I might as well not exist, and on top of all that I’ve been told that I’m very intimidating. So basically I suck at approaching people and I’m apparently very hard to approach.

I’ve been struggling with making new friends and communicating with people since I was in elementary school. I have no idea where to start or have any idea on how to go about this. Even when I contact people, they never seem to do the same back. Idk why, if it’s something I somehow managed to do or what. Any help or advice would be greatly appreciated.