1. The paint job on the cars left side has been destroyed and is the wrong color.
2. The cars shadow is missing and the car looks pasted on and hovering.
3. You can see stacked cinder-block bricks through the windshield and passenger side window.
4. Magic grass at the front and the back of the car.
5. Poor blending around the man.
I could go on but I won't. I really want to encourage you to ASK for help!!!! You can't get better unless you ask for help in learning how to do things in Ps.
The primary skill that I feel you need work on that would help you the most, would be improving your Clone Stamp skills. You can do this by watching YouTube related tutorials where you can practice on your own, or you can use a Clone Stamp Practice thread here in this forum where you can ask for help from our members.
You can also ask for help in this thread in working on this car.
For example: How do I remove the man's reflection from the hood?
Isolate the area by selecting with the Pen Tool....
Use the Clone Stamp Tool set to 20% flow and slowly clone out the reflection while making source samples often and directly adjacent to the target area.
Any additional details can be added using the Brush Tool set to 4% flow and a small round brush. Sample colors often. You have to match the colors!