For the sunset image i used the selection tool to select a general area of the model. After i had my selection area i used the refine edge tool and to change the pixels that were selected. Then I used the decontaminate selection box to get rid of the white in the background.

For the toronto image i made use of the nondestructive editing tools available in CS5. I used different adjustment layers. I used the saturation adjustment layer and dragged the saturation of the whole image down so that it was black and white.After that I went back in with the brush tool and painted a mask on the layer to revel parts of the image that I wanted to be saturated like the point.

For the final images of the mountain and lake I put all the images that i wanted to merge in the same folder then simply clicked automate-photomerge and then cropped the merge so that i had an image with square edges.