> do your hobby with other people, frequently

I think this advice can be refined.

The goal is to meet people with shared interests, regularly.

You may like to work out, but unless you enjoy talking and thinking about working out, the gym isn't the right place!

You may like to hike, but you may not enjoy talking and thinking about hiking. You may still find friends in the hiking group, because as you spend time together you discover shared interests. But you may also discover that you have very little in common with the people who like hiking.

That's why it's so easy to make friends in University: You spend a lot of time together AND you have a shared interest: The major you all chose!

On the other hand, if you're into ... trains... you need to find places where people go that like to talk and think about trains! That's not always easy!