It’s a cliche, but photography is all about light. I know those are just test shots, so I’m not even trying to critique them-- just wanted to mention that a shot gets instantly better with depth, and depth comes not only from focal length and framing, but also from interesting light.
The first Regen shot (from farther away) has some passingly decent and interesting light, showing off the depth of the cup; the closer crop of the second one is better. Combine those two and you have a pretty good photo. 
With your light game in place, the next thing is to experiment with different angles… and don’t be afraid to crop even tighter. Removing some of your subject is OK. It’ll be the same for cars. You’ll want a shot or two of the whole car, but the more interesting shots will be interesting crops. Even a photo that is primarily headlight and a bit of hood can be interesting from the right angle and with the right light.
Enjoy your adventure with photography!