Click on the following link to take you to a gallery of Emacs
screenshots showing the hows and whys I have added my own personal
additions to Emacs.

http://davinpearson.nz/screenshots

The most important and probably the most useful customisation that I
have is a drop in replacement for M-y.  Instead of cycling through the
kill ring, it brings up a window showing the kill ring in the order of
the kill ring.  You then click on the ENTER button of paste from the
kill ring to the last buffer you were editing.

In all my code I use the practice of prefixing all of my functions and
variables with <tt>dmp</tt> where DMP stands for Davin Max Pearson
which is my name.  I am unsure of just how useful this practice is for
adding to the Emacs sources.