Hi there, Jinny!
I am by no means an expert at car window photography, but I’ve done it my fair share, so I thought I’d chime in.
I would *highly* recommend rolling down your window whenever possible. This increases your [already low] chance of a good picture quite a bit. The glare and distortion of car windows (or any windows, imo) is so hard to overcome in pictures!
Shoot with your F/stop a little higher and switch your AF operation from AI Focus to AI Servo, because Servo is better at keeping moving subjects in focus.
With that being said, try to have a subject in every picture. Just a big empty picture of the plains is sometimes interesting, but even there, the interest is a lot better with some cool clouds or lighting. I, personally, end up with a lot of abandoned building shots from car windows, and there are tons of those in Colorado, if you want to try it yourself (I’m attaching a favorite old factory in Oklahoma I snapped driving about 50mph last summer).
A fun shot to try for from the car is a lone tree with negative space all around it. It’s hard to get angled right, but it’s on my photography bucket list! 🙂
Blessings!
Kimberly
P.S. Is your profile picture from the Air Force Academy? Colorado Springs is one of my favorite places ever! 🙂