If you want to get the latest tips and tricks for the current AutoCAD 2014, then Lynn Allen's Tips and Tricks booklet is the prescription the Doctor ordered.  

Lynn Allen's Tips & Tricks Book for AutoCAD 2014 (free PDF)
http://autode.sk/lynntips2014

If you haven't kicked the tires of AutoCAD 2014, download the free full version trial here and give it a try: http://http://autode.sk/ZdRG2i