Finding what exactly you love photographing is probably the second most importat thing is photography ! So it is great you have figured this out.
I am not into cars myself (honestly I consider them mechanical city rats that are able to spoil any street photo

- and I have a lot of such photos). But I probably have just a couple of casual car shots which I will take the liberty to share here wth you - just to give you some hints.
The thing with cars is that they represent a design. So in some ways shooting a car is like shooting an object of art. If you just shoot a canvas or a statue - they may be beautiful, so what? Where is the photographer's contribution, apart from documenting someboby else's wonderful work? What does he/she add to this beauty?.. So you have to ADD something to this design, not just make a copy of it, OK? You need to figure out how to do it, then your photos will have some aestetic value, independent from the car you shot... If you catch my drift.... If, for instant, you have created an image of a car with the sense of motion, drive etc, you have already added something. So if you are photographing an object of design, in order to create a good image it is useful to think in terms of "added value" : "What {aestetic} value do I add here?"
One thing to have in mind - as amolitor rightly says - the background. Clashing colors, lines etc can create an appealing image. I took this exactly because I liked the blue garage door and the way the blue color clashes with the red Mini and the straiht vertical lines contrast with the car curves. It is not a masterpiece by any stretch of imagination, but to give you a direction:
Another thing you can play with is reflections. Reflections are often bad with cars, as already mentioned. But sometimes it may be fun and can explore your creative side. That was a reflection of a house on the hood of a beautiful Audi TT:
So my advice - go beyond obvious, try to be creative and if you really love shooting cars, you will do much much better than these two images
