this has been posted numerous times before try searching for it next time wink: i use the right windows and menu keys for leaning because they're the closest to the arrow keys
Left shift and middle mouse - This ensures that you don't use any of the fingers used for movement when leaning, hence making it easier to lean and strafe at the same time and still be able to move in all directions.
Left Shift for leaning left and right mouse for leaning right i press the scroll button for secondary attack. If you play with this config for 3 days you will see an improvement in your play :)