Hi.
Looks allready good, But there are some Things i would like to come up with.
1. The carpaint Looks "flat" ...so the whole model Looks toyish. Corona has some Options to create cool looking car paints. You should check out some tutorials.
2. Same Thing with the interior leather. You should ad a bit more deapth to your materials. Build shaders, not just simple materials. This realy helps to increase the realism of your Images.
3.The presentation. Just look for some Images of cars. How they are lit. What Kind of perspectives do they use. Learn from other artists. Ad a bit of postproduction on top.
Hope i could help you.