For me, it helps to break down writing into smaller parts and training those skills individually.

Dialogue

Description

Background/characterization

Lore/worldbuilding/exposition

Instead of just throwing yourself into the vague idea of writing, try to think of it as several parts that paint a picture. If that makes sense.

I've been told that I don't describe enough characterization, so one thing I do is I look at at people in passing and instead of making assumptions, I start asking myself questions about them.

Are they there by themselves? Do they have any significant items with them? Do they have scars or tattoos?

Is the shirt they're wearing special to them?

Are they wearing a wedding band?

Is there something about their posture or the way they talk that sticks out to you? What could be possible about them that would surprise you?

Don't use it to make judgments about people. Try to create stories for these people.

I think writers like Rowling get it backwards and make a bad person and then give them traits they think are bad.

But one of the best tips I can offer is that you're writing a lot without even realizing it. If you catch yourself daydreaming or thinking of a plausible reason why something is, that's writing.

You can look at old texts you sent or funny things you said or heard. Not everything will suit what you need for a particular piece of writing, but everything can be useful.

Finally, think of situations that would be emotionally charged just for you and see if you can run with it.

For example, I was able to write a pretty good thriller story based on my own anxiety about people going through my things. Since it's a close (sometimes triggering) issue for me, I can write about that in a very authentic way.

What if your personal idea of heaven was the real one?

What if that conversation you messed up went the way you wanted it to?

It's okay if it's awkward or uncomfortable. Think of it like flexing a muscle. Until you get good at using it, you'll feel uncomfortable and then it'll be second nature.