To surprise the enemy Flash then instantly R once you arrive. Q E W as quickly as you can.
When you need to all in quickly Q R instantly and upon landing W E as quickly as you can, followed by an AA.
Your regular all in is Q then E quickly once in range followed by an AA. Hit W R as quickly as you can then AA.
To chase and burst a target Q then E and instantly Flash W.
For your basic engage use R. Upon landing instantly E Q then AA W.
To maximise your CC Use R. Upon landing instantly AA W followed by quickly using Q E then an AA.
Your basic combo against abilty based champs is to Q then walk forward, AA once in range and instantly W once it completes to reset the AA. Follow up with an instant E then an AA.
Combos against Auto Attack based champs are slightly different, AA then E Q instantly followed by AA W AA.