Switch between windows on Mac OS X?

On Windows when I do alt+tab I can switch between windows. If I have 5 firefox windows open then using alt+tab will switch between them.

On my MacBook, cmd+tab switches between applications, not windows, so it will switch between firefox and xcode, but not between two different firefox windows.

I am sure there is some way to use keyboard shortcuts to switch between active windows. What am I missing?

Cmd-` toggles through the windows forward.

Cmd-Shift-` toggles through the windows in reverse.

Cmd - alt - arrowkey switches between tabs

There's a 3rd party app called Witch which will let you cycle through all windows of all apps.