Watching folks like Clifton Hicks play, I've concluded that, at some point, you have to just let go and play the damn thing. So that's what I'm doing, and it's made all the difference in the world. The main thing it does is relax your hand ( and your mind ), so that you just kind of rear back and have fun, rather than put your nose right down on the strings, purse your lips, and meticulously pluck away, trying always to get it just right and by the rules.
Feel like throwing in an up pick right in the middle of your clawhammer tune? Go for it, and while you're at it, go ahead and toss in a down pick right in the middle of that Pete Seeger thing you're doing.
Sure, you do need to get the basics, I still practice scales, but after your fingers and hands remember ( Yes, I know fingers and hands have no memory ) those things, turn'em lose and let'em have fun.
Seriously, I think sitting down each session and focusing on immaculate playing is counter productive, after you learn the basics. And I believe the reason is that it keeps your hands tense, which inhibits their movement and, hence their ability to play accurately and/or with speed and fluency.
I'm surprised that concept isn't taught by music teachers. All the time I took classical and flamenco guitar lessons, from different teachers, I never had one of them tell me that. Those of you who have played sports know you cannot play effectively when you're all tensed up -- you have to relax. But we seem to think music's different, we have to concentrate on holding that hand "just right", etc. Well, the reality is that "just right" depends not just on banjo-playing rules, but on the player's anatomical and mental makeup as well. Just right for you may not be just right for me, and I'll never find my just right if I confine myself to playing according to your just right. Clearly there are commonalities between the way accomplished players do the job, but there are individual differences, too -- just watch two players and you can see that.
Sorry for the diatribe, but I feel elated, even if it did take me 81 years to get into this frame of mind. My new mantra is "Just let go and play the damn thing".