What's the good way to improve listening and speaking skills?

I just wanna know that when you learn languages, and you would like to improve your

listening and speaking skills, how do you study?

I mean, which kind of materials you usually use? For example, YouTube videos, apps, audio books...and so on.

The reason why I want to discuss that just because, I can communicate with native English speakers, but if they speak fast or if they use lots of idioms or slangs, I cannot catch the meaning sometimes.

I know why it happens because of my vocabulary and listening skills are not enough.

So I need to improve both of them.

And this is my question again.

Can somebody recommend me good materials to improve listening and vocabulary?

Also, I'd like to know which kind of materials you use when you study English or other languages as well.

Thank you.