Here is our base image



nice, but boring background, just want the car!



So use the background eraser tool set to the following



Now start removing the background, photoshop should pull it out for you automatically



now all the background is removed round the edges, time for a touch up, use the eraser to remove the rest of the background dont worry if you go to far over the car.



Now all the background is removed you need to tidy the edges of the car, select the history brush



and restore the edges of the car you didn't want to remove usually found where similar colours match



now use the eraser again to remove all the left over bit that you dont want and clean the edges up



Hey presto, finished!



Add a new layer behind the carm add a gradient map in layer style, finished