Illustrator tips to share..

Show/Hide Bounding Box
Here's a shortcut to show and hide the bounding box (Command-Shift-B; PC: Control-Shift-B). The bounding box is a great way to resize objects without switching to the Scale tool. But do sometimes the bounding box is very distracting, so the option to toggle on/off is quite a useful tip.

Locking/Unlocking Guides
By default, all guides that you add to a document are auto-locked. To unlocking all the guides in one quick step, press Mac: Command-Option-; or PC: Control-Alt-;. To works opposite: Once you've unlocked all the guides, use the same shortcut to lock all guides.

Quick way to delete from the palette
To delete anything from a palette, without getting a dialog like this example asking you to confirm your choice, hold down the Mac: Option key or PC: Alt key as you click on the palette's Trash icon. This applies to brushes, swatches, layers, etc.

Timing is a key factor
One of the important principles of using keyboard modifiers is that the same key will have different effects, depending on when you use it. For example, with the Direct Selection tool (A) active, holding down the Option key (PC: Alt key; MAC: Option key) will select the entire path. If you don't let go of the Option key while you drag and move, you'll get duplicate. So, to move a path without duplicating it, hold the Option key while pressing and click to select the path, release the Alt/Option key before dragging the path and move.

Switching palette's view
Most of the Illustrator palettes have more than one display size, reason for users to save more working space without closing palettes. Multiple sizes in some cases. You can use a palette's flyout menu to choose Show Options or Hide Options, or just to double-click on the tab at the top of each palette. To see if a palette has multiple sizes, just keep double-clicking on the tab to switch among the views size.