1. After editing a selection in Quick Mask mode, Alt-click the Standard mode (Quick Mask off)
button to invert the current selection.
2. When using the Marquee tools [M], use the Shift key to create perfect circles or squares: use
the Alt key to draw them from their center.
3. Use the Reselect command [Ctrl+Shift+D] (Select » Reselect) to load / restore your previous
4. You may alternate between Polygonal and Freehand Lasso [L], while you are creating a
selection, by holding down the Alt key.
5. Use the Space Bar to move a selection while drawing it.
6. Holding the Shift or Alt keys to add or subtract from a selection is fairly common knowledge,
but did you know that you could hold down Shift and Alt together to intersect two selections?
Tip: Ctrl-click on a layer thumbnail (in the Layers palette - to load its transparency channel) and
then Ctrl+Alt+Shift-click a second layer to intersect the two layers' transparency masks.
7. Retain your selections while scaling or duplicating an image by first switching to Quick Mask
mode [Q] (or click on the Quick Mask icon near the bottom of the toolbar).
8. Alt-click the Quick Mask button to toggle between masked or selected areas.