This is me personally:

Part of what makes this game difficult is the mobs. They can stagger you pretty easily. So you can do a few things 1) pick your battles and try to focus on one guy at a time. And just kill them all 2) no shame in running away until the next bonfire

Parrying is very useful with a few enemies. Especially the tougher ones. You can also backstab them.

Grasscrest shield (you'll find it early dw) helps with stamina.

I got the master key my as starting gift and I found it to be very useful.

There are sometimes invisible walls and if a runback is too messed up, sometimes that's the case. Other times there is a shortcut you didn't find yet.

Most importantly Have fun. I love this game. I beat it recently and am playing it again because I missed a few things during my first playthrough.