How does one switch between windows on VIM?

I'm using both Vim and MacVim (or well, trying to). I installed the Tagbar plugin but find it impossible to switch to the actual Tagbar window to make my selection.

I've been reading loads about window switching in VIM, found a lot of default keybindings (CMD+`, CTRL+W+↑ or ↓), tried setting my own. NONE worked.

I always use VIM for quick file edits and got intrigued by using it as my full-time IDE. After spending a full hour just trying to figure out how to switch a window I'm totally turned off by the idea though. Still, I feel I have to know. How do you switch the window? Am I being totally blind here?

Control+W followed by W to toggle between open windows and,

Control+W followed by H/J/K/L to move to the left/bottom/top/right window accordingly,

Control+W followed by Left/Down/Up/Right arrow to move to the left/bottom/top/right window accordingly.

Control + W twice does the trick for me on Macbook Pro.