2) Layer -> New Adjustment Layer -> Selective Color. I used these settings:
To get rid of the yellowish shine of candles in the pic, I fiddled around with especially the yellow and reds. To make the green of the ivy around Ryan's neck come out a bit better, I played around with, of course, the greens, but also the neutrals. By making some changes on the blacks, I changed the brightness of the colours in the picture a bit.
3) Add another Selective color layer, with these settings:
I wasn't entirely satisfied with the colouring, yet, so I made some more, changes.
I lowered this layer's opacity to 63%
4) Layer -> Flatten image.
5) Open a new canvas and fill it with black (#000000)
6) Drag your picture into the canvas.
7) I erased those few cushions you can still see on Ryan's left with a soft brush.
8) And to finish the wallpaper, I added some text. I used the font 'Mia's Scribblings' to write 'Ryan Ross' and the font 'Cheryl' to write 'Into a room where it's nine in the afternoon'.
If you got any questions/remarks, shoot! :)