RESIZE
 
> you can resize the canvas IMAGE >RESIZE>CANVAS SIZE (resizes the canvas)
> or resize the  image           IMAGE >RESIZE>IMAGE SIZE  (resizes the image)

DRAG an IMAGE to another canvas

> click on image (to move) with select tool and drag onto the other canvas (then arrange it on the layers window and resize if required)

To SKEW an image press control and grab a control box on a corner of an image and drag to skew.

Or  PERSPECTIVE
 IMAGE >TRANSFORM>PERSPECTIVE

LAYERS

> always keep your layers window OPEN
> convert any layer that is called BACKGROUND (as opposed to layer)
> a layer higher in the window than another can appear on top of a layer below it
> new layers can be deleted by dragging the layer to the trash bin on the right
> create a new layer by clicking on the middle (2 squares)

CLONE STAMP TOOL

How did Mr. Bush become so all seeing ?
The CLONE STAMP TOOL is placed over the eye and ALT is pressed now you can paint an eye and more elsewhere on the canvas.
Setting up a new layer to stamp the clone ia good idea.

More PhotoShop Tools
Make a Photo Collage
More tips for Photo Collage