How do you get customer validation?

Hey, I'm a wantrepeneur and developer, and while I'm generally pretty good at the product side of things, I am absolutely god awful at marketing and getting an idea off the ground. So far its mostly been myself building an app or website, and then, I lose direction and don't really know where to go from there. In general I want to be a little bit more conscious of where I may gain traction and how I initially get started making sure theres people that like and will use what I'm building. So, I wanted to ask you guys how you do it, and where do I get started when it comes to things like market fit, customer discovery, and product validation. Thanks!