Rotate and Crop at the Same Time:
When you are using the Crop tool, you can rotate while you crop by just moving your cursor outside the bounding box that appears around your image when you choose the crop tool. You will see that your cursor temporarily changes into a double-headed arrow, which enables you to freely rotate your object. When it's rotated just the way you like it, you have two choices: Double-click inside the bounding box, or just press Return to make the rotation permanent.
How to Cancel a Crop:
If you are using the Crop tool and decide you don't want to crop the image after all, just click once on the Crop tool icon in the tool palette. A dialog box will appear giving you the option to "Crop" or "Don't Crop.
Free Transform Tips:
To bring up Free Transform, press Command-T (PC: Control-T). Here is how the Free Transform tool works:
To Scale (resize) an object visually, just grab one of the corner and drag in or out. Hold down the Shift key as you drag to keep your image proportional.
To Rotate an object, just move your cursor outside the bounding box and the cursor changes to a two-headed arrow which enables you to free rotate.
To Distort an object, hold the Command key (Control key on a PC) and grab any corner and drag.
To Skew an object, hold both the Option-Command keys (Alt-Control on a PC) and drag a corner left or right to Skew.
For change the Perspective of an object, hold Shift-Option-Command (Shift-Alt-Control for a PC) and drag a corner up or down, left or right.
If all these commands seem too confusing (and frankly it is a bit hard to keep them all straight) you can always just hold the Control key and click anywhere (or on PC, just rightclick) and a pop-up list of transformations will appear, and you can choose the one your looking for. When you do, the bounding box doesn't change, but the cursor changes to the right one for the transformation you selected. You can now just click and drag away!
Editing Gradients:
To bring up the Gradient Editor, get the Gradient Tool, then click on the current Gradient up in the Options Bar. To create your own custom gradient, click below the color bar to add another color to the gradient. To assign either the foreground or background color to this new color, click the "F" marker for foreground, or the "B" marker for background. To choose a different color altogether, just click on the rectangular swatch next to the F and B markers and the Color picker will appear, enabling you to choose any color you'd like. To delete a color, click and drag down to the bottom of the palette; it will disappear. To drag out an existing copy of a color already in the gradient, just Option-drag it (Alt-drag on a PC.)
Get the Zoom Temporarily:
To temporarily switch any tool you are working with to the Magnifying Glass tool, just hold the Command-Spacebar (Control-Spacebar on a PC).
Tip for working while zoomed in close:
To temporarily switch any tool you are working with to the Grabber Hand, just hold the spacebar. Perfect for navigating while zoomed in close, because the Scroll Bars move too far, and are too unpredictable when zoomed in.
Get the Eyedropper Any Time You are Painting:
If you have any paint tool (Brush, Airbrush, Pencil, Eraser, etc.) you can temporarily switch to the Eyedropper tool (used for sampling any existing color from a image) you can just hold the Option key (Alt-key on a PC).
Toggle Through The Tool Palette:
To instantly switch to the Rectangular Marquee tool just press "M". To get the Elliptical (circular) Marquee tool, just press Shift-M.
To get the Crop tool (you have missed this tool have not you?) just press "C".
To toggle through the Pen tools press Shift-P to toggle between the Pen tool, the Magnetic Pen tool, and the Freeform Pen Tool. To get the Add Anchor Point Pen press the "+" (plus) key. To get the Delete Anchor Point Pen press the "-" (minus) key. Press the letter "A" to get the Direct Selection tool, and unfortunately there is no keyboard shortcut to get the Convert Point tool.
The rest are pretty obvious (E for Eraser, B for Brush, T for Type, etc.) with the exception of:
"I" for eyedropper
"K" for Paint Bucket (You don't really use this tool, do you?)
"N" for the Line tool
"O" for the Burn tool
"R" for Blur tool (Should have been R for Rubber Stamp)
"U" for Smudge tool
"Y" for Pencil tool
