Looking good man. As others have said, there are some fundamentals of proper riding, but what's paramount is that you're comfortable and able to control the inputs you're putting into the bike.
As hard as it is (I hated this advice too), take your mind OFF of trying to drag a knee, and just focus on great form and getting really consistent with that form. With the improvement in inputs comes speed, and with more speed comes more lean, and with more lean, you'll be feeling out the curb with your pucks before you know it. Making a dragged knee your focus though is likely to end with a lot more than your puck dragging on the ground.
Do loads of track days, and LISTEN to the instructors' inputs. Get as many of them to follow you around as you can - they'll usually have great input about your lines and your body positioning. Listen, implement their feedback, rinse/repeat.
Most of all, HAVE FUN doing what these bikes were designed to do!
I have some bikes. I like to ride them.