You have two completely different brightness/contrast pictures.
In your case, tone down the color in the skier using 'Levels' or 'Selective Color' or just flat out messing with the Hue and Saturation meters. The skier needs more of a blueish gray tint to match the darker shot behind it. Even the slightest bit makes a huge difference.
Anybody can cut out an image these days, but the hard part is matching all that fun shtuff.