Lesson #1: Always take your bottle of water in with you. Leaving it in the car is stupid and you'll spend the last 10 minutes on the treadmill lusting after it.
Lesson #2: Take a towel. I never understood why people took towels to the gym or why articles on gym etiquette talked about cleaning up any sweat you dripped - I always wondered how people could be sweating so much. I get it now and will be taking a towel with me from now on.
Lesson # 3: Being stubborn isn't always bad. I'm a typical Scorpio in that I'm totally stubborn and this paid off today when I kept thinking "I'd really like to get off this thing" because then I'd think "No, I haven't hit my time yet" and "That old guy over there hasn't stopped yet and he's been on here longer than you!" Yeah, sometimes stubborn = good.
Lesson # 4: The elliptical is hard. Seriously, really hard. First it took me a minute to figure out how to get the dang thing to go, then my arms and legs were not wanting to work together and kept all trying to go in different directions. Once I finally got it figured out I realized that the machine is just hard in general. I thought I was going to fall off, or at least my legs were going to fall off. Needless to say I didn't last long on there, but never fear: I will conquer the elliptical. Mark my words.