Quick or Hot keys that are pretty universal to any package
General

Ctl C = Copy
Ctl V = Paste
Ctl A = Select All
Ctl D = Deselect All
Ctl Z = Undo last step - some packages let you set how many undos (10, 50 or 100)
Ctl S = Save
Ctl Q = Exit
F1 = Help

Shift Return = Soft line break <br>