I definitely think looking forward is more important that looking back, but you still have to have some kind of scale to measure progress. I think the first question you should ask yourself is "Do my December 2010 pictures look better than my December 2009 pictures?", if you can't answer this yourself, ask someone you trust. I'm not saying you need a report card, but you need to be making progress.
So here's my answer to that question, a year ago, I was doing some decent car photography, but then again I was also contemplating getting into Advertising work, messing around with Model Mayhem, and generally wasting my time with other non industry related photo projects. Frankly, my portfolio was a little scattered and full of filler images, my blog was mainly about product reviews and other techy topics.
Then last December I came up with the Message in a Bottle project (initially called Paper) and photographed 20 people for it; but that first half of the year I was still fumbling about with random shoots and blogs until around June (apparently that's when I decided to get more serious).
In the following 6 months I only added 8 portraits to Message in a Bottle, but I built a portfolio of Classical Musicians, and my blog took a direction that is more about photography and less about the gear. For the whole year of 2009 I wrote 17 blog posts; in November 2010, I wrote 18.
Overall I think I'm doing ok, but to take it to the next level I'm going to need to hit it twice as hard in 2011. That means more musician shoots, more Message In a Bottle portraits, more blogging, and a greater concentration on marketing myself.
Overall I give myself a B+, I did well but I could have done more.