One of the most important things you could ever do is track and manage your analytic data religiously. The scariest thing to me is seeing the sheer volume of dealership websites who have NO Google Analytics or Webmaster Tools tracking code on them, whatsoever. Let alone custom reporting and alerts, which not many people even in the mid-to-upper echelons of marketing have an entirely firm grasp of.
This is equivalent to throwing a ball, closing your eyes and hoping it makes it without even knowing if a hoop exists for it to go into. With proper configuration and integration you can literally have an outline of where every little piece of traffic originates, how they use your site and where you can improve or capitalize. This also helps you identify things that are wasting your money by sending garbage traffic.
I always come across people complaining about the ROI in Social Media but I think they just might be unaware of how to track it.
Do you know how many visitors your site gets from all that posting you do on Facebook? How about all those YouTube videos you're (hopefully) posting?
Do you know how many of those people actually put in a lead? And which pages they looked at before they did it, including which page they submitted the lead on, using which form?! How about what pages they went to afterwards?
Do you have daily reports showing the % of new visitors who visit your site from each of the towns within a 25, 50 and 100-mile radius?
Are you alerted any time a certain page or specific traffic medium fluctuates very unnaturally so you can track technical issues such as broken links or search engine listing problems (like when Google does updates?)
I can compile and monitor all of this and thousands of other things that all have profound impact on your strategies and success once you can take advantage of knowing them.