The most common engage uses W then E, then run up and R. Q while dragging the enemy then turn around right as your R is about to end and instantly AA. Continue to AA Q afterwards.
With higher amounts of Ability Haste E then W and walk up to AA Q AA. Use R, then Q them as you drag your target around. Spin right as your R ends followed by an instant E AA Q.
If a little closer or they're slowed W then R, use Q as you drag the enemy then spin right before the R ends and instantly E AA Q AA as quickly as you can
After level 6 gank with W then E, AA Q instantly then AA R. Q while you drag the enemy around then AA and Q as needed.
A normal gank will lead with W then E, use Q right before you AA, then AA a second time followed by Q AA.
When already in melee range Q AA instantly then E AA as quickly as you can. Q AA and continue to AA then Q whenever it's up.