Adjust the object size from the center

[hold] Option(alt)

Scale object proportionally from center

[hold] Shift - Option(alt)

Duplicate object by drag

Click and drag object while holding Option(alt)

Copy/Paste Style between objects or between mobile/desktop via Special Paste

-Copy Styles: Select first object and Copy with ⌘(Ctrl) + C
-Paste Styles: Select second object or switch to mobile/desktop and Special Paste with Shift + ⌘(Ctrl) + V

Snapping of Objects

Toggle on/off with ⌘ (Ctrl) + ;

Zoom In/Out of Stage

[hold] ⌘(Ctrl) + Scroll

Reposition Stage

[hold] Space + Click & Drag

Multi-Select Layer Locking

[hold] ⌘(Ctrl) + L