Split The Current Window

Generally when I want to open up a buffer in a window split, I use :sp or :vsp and type out the filename. It may be a bit more convenient to use window commands to create the splits.

To open a horizontal split:

Ctrl-w s

To open a vertical split:

Ctrl-w v

With the split made, you can use Ctrl-o/Ctrl-i, BufExplorer, or whatever way you like to navigate between buffers.

h/t Ryan Messner