Do not use the photo above! Find your own photo with a good amount of background/extra stuff that will become black & white, and two things that you could paint in to be color.
Black & White Copy
First thing we want to do is make a copy of the photo in a new layer.
The top layer we will make black & white - under COMMAND>Creative... choose "Convert to Grayscale", or go to FILTERS>Hue & Saturation... and
check the box for "Colorize" and pull Hue down to "0".
Add Color
Add a mask to the top layer.
Zoom way in.
With a black Brush, reveal the colorful part from the layer underneath you want to reveal for 2-3 things.
Play with the settings like the brush softness/edge.
You also may need to undo something with CTRL+Z or use a white brush to hide the layer underneath.
If you want, Crop the photo to just the part you want.