My husband learned some from his dad. And we're both engineers, so keep that in mind.
When he was a kid, he took things apart and put them back together.
When he was in college/out of college, he learned to cook by getting his mom's recipes and trying them.
When he was out of college, he would buy a "kit" to build your own computer, and work on it.
Now he's pretty good at a lot of stuff. We have books on how to do things. First, he started with borrowing from the library on plumbing, electrical, etc. If the book was really useful, then he bought it. The internet is a good source also.
He built our kitchen cabinets too. He learned about cabinetry/woodworking by taking adult ed classes at the local high school. Which is how I built my skills in cooking/ quilting.
Man, I sound like such a girl. I do like helping him with projects, but with two kids, we tend to divide and conquer these days. So mostly I do the girly things. Patching clothing, hemming pants, making curtains, cooking, etc.