I'd recommend Python. It's very beginner friendly, there are plenty of tutorials, and there are a lot of advanced libraries. [1]
Don't read the manuals, follow a few tutorial. Try to think a variant of the exercises in the tutorials and try to code the variants too. (Each person has their own style, I don't like reading the manuals. You may like to read the manuals.)
Try to find a problem in your area that is easy to automate. Some thing that is small, repetitive and boring. It's good to make a few toy/small projects that make something that is useful for you.
I don't know how realistic is to expect some side money from this, but if you are an expert is some field sometimes you can use programing to solve exactly what the people in that field needs.
[1] I prefer racket. It has a strange syntax, so sometimes people get scared of it. The advantages of racket are easier to see when you have been programing for a while, so start with Python and then try other languages later.
Don't read the manuals, follow a few tutorial. Try to think a variant of the exercises in the tutorials and try to code the variants too. (Each person has their own style, I don't like reading the manuals. You may like to read the manuals.)
Try to find a problem in your area that is easy to automate. Some thing that is small, repetitive and boring. It's good to make a few toy/small projects that make something that is useful for you.
I don't know how realistic is to expect some side money from this, but if you are an expert is some field sometimes you can use programing to solve exactly what the people in that field needs.
[1] I prefer racket. It has a strange syntax, so sometimes people get scared of it. The advantages of racket are easier to see when you have been programing for a while, so start with Python and then try other languages later.