Here's an idea that will put you in the lead Jim. And please don't take this as a commentary about your photos because I've never seen them. Read the tutorial about histograms as they apply to digital photography at
If your camera doesn't have a histogram feature, borrow one that has or try to picture the histogram function in your mind. I used to do that using a spot meter for 35mm photography. I'll even loan you my spot meter if you like. If you've never used a spot meter, you will be astonished to see the differences in contrast range for the same scene morning, noon and dusk.
The idea of a histogram is to not have data clipped at the edges of the chart. The edges represent full saturated black or white. Also, the data should not be clustered in the center. That means the photo will be dull and lackluster. You can't see these things in the view finder. Well, maybe Ansel Adams can. If you don't get a nice histogram, you need to come back when lighting is suited. Make yourself a project notebook of camera settings, time of day, how the histogram looked and match that up with photos you take. When you get home, calibrate your monitor. Then review your results against your notes. Once you're getting the results you want, go back and stage the photograph. Don't forget to bring a tripod. Sometimes the best lighting situations require a steady camera to be sharp.
If you can find a cop who will help play along I have an idea for a really cool photo. Guys, this idea is for Jim, so don't copy. Find a pretty country road setting free of urban distrations. Stage your car pulled over by police or the sheriff with the bubblegum lights on. Emotion is what these photos for the calander should convey. Nothing says muscle car like trouble with the law. Get a nicely done photo of that, I guarantee you'll win. Don't forget to wash and wax the squad car first. I know you're car would already be under four coats of Zaino. It's all about the details, my friend.