Got no ACL so this is crucial to me even playing at all!
When I start to get issues with this I take up my stance and jam a ball under the outside of my right foot. This has the effect of locking that part of your body and gives you the feeling of a flexed right knee.
Dont swing full out! Make an easy swing and just get the feeling,then take it to the course.
No specific tips other than to suggest filming your swing from the front, back, left and right and watching the replays in detail. This might give you a better idea of what is going on in the knee department