My social skills are absolutely horrible, and i’m not quite sure how to build them up.

Almost every social encounter that isn’t with a close friend usually turns out awkward just because I can’t seem to put my words right or i run out of things to say. As a result I kind of stopped trying to socialize with anyone who isn’t my close friend. And now its gotten so bad that i cant even bring myself to say hi to my own co workers. It’s a horrible feeling. Wanting to talk about things with people but not being able to let the words out my mouth. Any tips on how to build myself back up to talking and having conversations with strangers and acquaintances.