I need to build a site that has several feature boxes and some links that are common to various parts of the site. What's the best way to achieve this?

The feature boxes don't appear on every page and the client wants to edit the content of these boxes.

The links appear as 3 columns in the bottom of the site. These also need to be edited by the client.  It's not practical to change these links on every page of the site, if added manually nor is it practical for my client to start editing skins or templates. 

Is there a way to create common content items and them pull them into the pages where they are required?  Like you can in Joomla by creating custom modules.  In fact it's something I've done with every CMS I've ever used just can't seem to think of an easy way with DotNetNuke.  I can create a template, or skin.  Maybe I need to look at creating custom modules that the client can edited, somehow.