Duplicated the background set blending to multiply to get darker effect
step 2 of 6
Added the girl, gave her some adjustment layers to fit more in the background. Placed some shadows under her and on the left side.
step 3 of 6
Added the bear, gave it adjustment layers and some shadows
step 4 of 6
Created a white border around the photo's. With the pen tool created a torn line, split the photo in two on that line. Added them on the ground and gave them some adjustment layers and shadow
step 5 of 6
Placed the posters on the wall. Gave them adjustement layers. On the clownposter i made the shadow from the ladder appear.
step 6 of 6
Gave the final result some adjustment layers to make it all blend in.