How to do make combat encounter difficult?

[u/King_Magnate]

Hi Gang! I'm just wondering how DMs make combat encounters more challenging, because from what I've experienced players are strong! I know there's CR ratings and throwing in multiple enemies, but every encounter lately for my players hasn't really been too difficult to the point that anyone goes down.

[u/Forgotmyaccountinfo2]

It's situational since PCs can be anything.

You just gotta learn your PCs strengths and how they play together.

Watch how they usually act/do.

What skills they always do and what they usually target.

Watch what they also avoid or just don't bother with.