For more burst quickly use W and E, then AA. Follow up with Q and R, then AA again.
For a longer range trade use W then E while channeling. AA, then Q and AA again.
To trade when in close range E then instantly Q your target, then AA W and AA.
To dish out some quick damage use W and AA, then Q immediately after.
To full combo when in close range quickly use Q and E, then AA and W. AA then R and AA again
For a long range execute W, then quickly Q and Flash mid animation.
For a nice gank setup channel your W and then Flash.
To execute a low target, Q and then Flash mid animation.