Use the minified versions of all the .css
and .js
Yes, that's a good step towards reducing file size. You can also use gzip
compression to compress everything sent to client browsers, as explained here by Google: How gzip compression works
Load the common library elements (jQuery, etc.) from some common source. Not sure what the source that's most likely to already be in the browser cache is.
For jQuery, you can use the URL to the jQuery library on their site or Google's jQuery library, which are already minified:
<script src="http://code.jquery.com/jquery-1.10.1.min.js"></script>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
These URL's are used by many sites, so might be cached - in any case, they use very fast content delivery networks (CDN).
The other option is to use a CDN yourself, which will compress your data for you, as well as serve it from multiple locations closest to the client, in parallel, and may cache it also. Here is an article which discusses the use of CDN's focusing on Twitter Bootstrap, but applicable to many such frameworks.