1. open up your image. for this tutorial i'll be using this picture of keira knightley

2. duplicate the picture by going to layer then clicking duplicate layer, something will pop up; click ok

3. add a layer mask to the layer you just made

4. select the thumbnail of the picture in the second layer

5. make the image black and white by going to image, then adjustments, and click desaturate

6. click the layer mask thumbnail

7. make sure the color black is selected

8. click the brush tool

9. adjust the brush size and softness depending on what you are going to make color again

10. slowly brush over the parts that you want to be in color and after they are brushed over they should be back in their original color.
if you make a mistake just change the brush color to white and brush over the error and go back to black to continue coloring

11. color over everything you want in color and then you're done

comment if you used/found this tutorial helpful