One of our Photoshop tutorials was to use adjustment and blending to turn the silver car a different colour.
Firstly, I used the polygonal select tool to select all around the background, avoiding and deselecting the car. Once I did that I went up the the Select tab and chose the Save Selection tool. I then used the Brush/Pen tool, choosing the colour red, to colour in the red mini car selection.
If I could improve on something I would use hue saturation to change the background colour to black and white like how we were shown in the tutorial example.