R then E as soon as you land. Flash instantly as you start the animation to extend the range and quickly Q eAA.
W then E and while mid E animation, Flash to extend the range. Follow up with Q eAA.
When close range W AA instantly, E Q AA as quickly as you can right after then continue to AA.
Your standard combo will be E then instantly W AA, Q as soon as the AA completes to reset your AA animation then continue to AA.
If you're already close to your opponent W right before using R then E Q eAA as quickly as you can after landing.
After level 6 R forward then E once you land, use W to get close then instantly AA Q once in melee range, followed by more AAs.