How do I configure printing to format properly?
This is a known bug that is fixed in 4.6.11--I discovered it on a client's site.  Basically, if your report doesn't have the header explicitly saved in the report settings, the header is blank rather than the default.  The default header contains the CSS to make your report look like it should.

The simplest solution is to upgrade, or you can apply the diff.

Finally, a rough option is to edit the header and footer manually.  Your header should be:

&lt;html&gt;
  &lt;head&gt;
    &lt;title&gt;CiviCRM Report&lt;/title&gt;
    &lt;meta http-equiv='Content-Type' content='text/html; charset=utf-8' /&gt;
    &lt;style type="text/css"&gt;@import url(/wp-content/plugins/civicrm/civicrm/css/print.css);&lt;/style&gt;
  &lt;/head&gt;
  &lt;body&gt;&lt;div id="crm-container"&gt;


and the footer should be

&lt;p&gt;&lt;img src="/wp-content/plugins/civicrm/civicrm/i/powered_by.png" /&gt;&lt;/p&gt;&lt;/div&gt;&lt;/body&gt;




You'll need to paste this in for each report, so it's more efficient to just upgrade, but if you're in a pinch trying to get the report out right away, this will help.