To create a skin, you need to have notions of one or more of:

• XHTML
• CSS (Cascading Style Sheets)
• Velocity Templates
• The XWiki API

Usually you just want to change the basic layout of XWiki, and therefore you need to modify:

• the main styles file: style.css
• the header template: header.vm
• the footer template: footer.vm
• the main logo

• Create an empty page
• Attach any images needed in the skin to this page
• Select "Edit Objects" in the "More actions" menu
• Add the objects from the class "XWiki.XWikiSkins"
• Modify the style.css (overriding standard rules)
• Modify header.vm and footer.vm content

• Default Styles: http://www.xwiki.com/xwiki/skins/default/
• Default Templates: http://www.xwiki.com/xwiki/templates/

If you want to derive your skin from another skin, you should write the name of the skin to derive in the "baseskin" textfield at the bottom of the page.

It is possible to modify the other templates. To do so you need to edit the XWiki.XWikiSkins class (using the Class Editor) and add a TextArea field that has the name of the template (for instance if you want to modify viewheader.vm which takes care of the action bar at the top, you need to create a TextArea field named viewheader.vm)

Once you have make some modifications, you can test your skin by adding the "skin=Main.MySkinPage" at the end of the URL. For example if you are creating a skin on xwiki.com, you can test the skin on the Home Page at http://www.xwiki.com/xwiki/bin/view/Main/WebHome?skin=Main.MySkinPage

Finally, when you are really happy with your skin, you can apply the skin to the whole wiki or to a space by modifying the "skin" field in the XWiki or Web Preferences. You should also modify the default and alternative styles (If you haven't created alternative styles, put 'style.css' in both fields)