1. Easier marquee selections
Hold down Alt to start a selection at the centre point with any Marquee tool, and then hold Space to temporarily move the selection around.
2. Undo, undo, undo
You probably know that Cmd/Ctrl+Z is Undo, but you may not know Cmd/Ctrl+Alt+Z lets you undo more than one history state.
3. 1000 history states
Go to Edit>Preferences>Performance to change the number of History states up to a maximum of 1000. Beware though of the effect that this has on performance.
4. Cycle blend modes
Shift + or – will cycle through different layer Blend Modes, so long as you don’t have a tool that uses Blend Mode options settings.
5. Rotating patterns
You can make amazing kaleidoscopic patterns with the help of a keyboard shortcut. Cmd/Ctrl+Shift+Alt+T lets you duplicate a layer and repeat a transformation in one go. To demonstrate, we’ve made a narrow glowing shape by squeezing a lens flare effect, but you can use any shape, image or effect you like. First, make an initial rotation by pressing Cmd/Ctrl+T and turning slightly, then hit Enter to apply. Next, press Cmd/Ctrl+Shift+Alt+T repeatedly to create a pattern.
6. Combine images with text
There’s a really easy way to overlay an image on top of text. Drop an image layer over a type layer then hold down Alt and click the line between the two layers in the Layers Panel to clip the image to the text.
7. Bird’s eye view
When zoomed in close, hold down H and drag in the image to instantly dart out to full screen then jump back to another area. One of the best Photoshop tips for viewing work!
8. Funky backgrounds
Want to change the default grey background to something more funky? Shift–click over the background area with the Paint Bucket tool to fill it with your foreground colour. Right-click it to go back to grey.
9. Close all images
To close all of your documents at the same time, Shift-click any image window’s close icon.
10. Spring-loaded move
While using any tool, hold Cmd/Ctrl to temporarily switch to the Move tool. Release to go back to your original tool. Note that spring-loaded keyboard shortcuts work for other tool shortcuts, too.