Nice! Pretty good for a beginner.
Here is a very simple and effective way to change colour:
- Get the polygonal lasso tool (second tool on the left column), and select the whole car body (not the wheels).
- Then press Ctrl+C, then Ctrl+V.
- Use the lasso again to select parts of the car that shouldn't be coloured, like the windows. Delete these parts by hitting Delete while they are selcted.
- Then go to Image > Adjustments > Variations.
- Click on the colours to change the colour of your car
To put new wheels on:
- First find a pic of the wheels you like, and make sure they are at the same angle as the car.
- Use the polygonal lasso to select the wheel and do Ctrl+C Crtl+V.
- Use the lasso again to cut out the holes between the spokes.
- When you're done, get the arrow pointer tool and drag the wheel onto your car pic. It should automatically copy itself onto a new layer.
- Press Ctrl+T to transform the wheel and make it the right size.
- If the colour of the wheel looks out of place on your picture (it might be too bright or dark), then go to Image > Adjustments > Curves and move the dot around to make it look right.
If you need any more help just give us a shout