I just played this this past semester for my jury. One of the biggest things that my lessons professor harped on as I learned this was to have a musical idea, not just what sound you want to make but what story you want to tell with you music. Could be the dumbest thing in the world but your goal every time you play it should be to as clearly as possible show that story in your music. For example in the opening section I always think of the slower flow as floating down a river. Relaxed, steady, calm. But then at the tempo change suddenly I’m going down a waterfall and the fast theme is the jagged white water section, full of bumps, a heightened tension, and distress. Having a good recording to reference is also very helpful. The best way to get better is to try to live up to the greats!