MediaWiki-l Case Study: Skinning Media Wiki
lists.wikimedia.org/pipermail/mediawiki-l/2013-May/041162.html
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
The purpose of this thread is to give you an overview of how I went about skinning Media Wiki from the point of view of someone who has never attempted it before. I've used Media Wiki in the past but never done anything besides changing the default logo.