New to herb gardening

New to herb gardening

Hi guys. First of all, I have a bunch of basil, cilantro, rosemary, thyme, and sage currently. What I need help with is: How do I harvest them each when they are ready (how do I know when they are ready even???) or when I want to use some of the herb? I am afraid I am going to pull something off and hurt one and possibly kill it. For example, the thyme looks as if it's ready to be harvested. There's SOOOO much of it. I don't even know where to begin. Do I just pull some of the leaves off or do I take stems off? How do I harvest the other herbs? Thanks a lot!
My room!

My room!

Finally posting some pics, of my bedroom at least!

Finally posting some pics, of my bedroom at least!

i definately dont heart my room.

i definately dont heart my room.

Plant ID help

Plant ID help

Echinacea

Echinacea

Newbie Alert! *waves*

Newbie Alert! *waves*