Back in 2010, I wrote a guide for MakeUseOf.com, titled The Awesome Guide for Mac OS X. Though it's now a little dated, it is still useful for those new to Mac to the Mac features and applications that come installed in Mac OS X. (Note: use this link to download the guide directly to your Mac.)
The guide includes step-by-step instructions and lots of screenshots for using smart folders, setting up iTunes playlists, creating iPhoto smart folders, smart Mailboxes, and getting started with Automator.
I will be updating this guide, but for now, it's a good introduction to the topic. I suggest spending a Saturday and working through the tutorials. Once you start using Mac automation, you'll get more out of your Mac and reduce the amount of redundant tasks you perform on your Mac.