Editing Vimdiff

To switch windows in vimdiff or
to navigate windows in vimdiff or
to change windows in vimdiff try the following:
The ":vertical" command can be inserted before another command that
splits a window.

MOVING BETWEEN WINDOWS

        CTRL-W h        move to the window on the left
        CTRL-W j        move to the window below
        CTRL-W k        move to the window above
        CTRL-W l        move to the window on the right

        CTRL-W t        move to the TOP window
        CTRL-W b        move to the BOTTOM window

  Moving windows
==

        CTRL-W K        move window to the upper
        CTRL-W H        move window to the far left
        CTRL-W J        move window to the bottom
        CTRL-W L        move window to the far right

Source: [https://groups.google.com/forum/#!topic/bash-tips/kOzx8FVTVOc]

==

This looks terrifying at first, but let me explain what is going on.
From left to right, top to the bottom:
*LOCAL — this is file from the current branch
*BASE — common ancestor, how file looked before both changes
*REMOTE — file you are merging into your branch`
*MERGED — merge result, this is what gets saved in the repo

Let’s assume that we want to keep the “octodog” change (from REMOTE). For that, move to the MERGED file (Ctrl + w, j), move your cursor to a merge conflict area and then:
:diffget RE

This gets the corresponding change from REMOTE and puts it in MERGED file. You can also:
        :diffg RE  " get from REMOTE
        :diffg BA  " get from BASE
        :diffg LO  " get from LOCAL

Save the file and quit (a fast way to write and quit multiple files is :wqa).
Run git commit and you are all set!

[http://www.rosipov.com/blog/use-vimdiff-as-git-mergetool/]