Hey welcome to blender!
I’ve been using blender for a while now but I still haven’t found my ‘artistic’ edge yet so bear with me.
It looks really good for a first go and I can see you put some work into it.
The base mesh looks good however I would consider adding some details like license plate, review mirrors, and door handles. It would surprise you how much small details like this help to make a model look way better.
Also have you tried the edge split modifier? It’s useful for making sharp edges on a smooth model.
Be sure to uncheck ‘From Edge Angle’ if you don’t want it to automatically sharpen edges based on angle.
You can mark edges as sharp by pressing CTRL+E on the keyboard and then selecting ‘mark sharp’.
Hope this helps!