Some good advice ITT, picked up a few things I will look at myself.
My winrate at 50NL is alot better than it used to be these last 3 months/65k hands and I found that the following things have helped me alot. Nothing to do with stats e.t.c. but my 2 cents worth.

1. I used to tilt a fair bit like alot of players but I have now put a (near) stop to that and it must have saved me alot of bb/100. I know it is hard when you are running bad but running bad + tilt is alot worse. Not tilting is a massive edge over most other players. Now I feel I have nearly mastered the tilt demons I can now work more effectively on the theory side of the game, improve and move up again sooner rather than later.

2. I take regular breaks instead of grinding long sessions and only play when I have planned to play. My "impulse" sessions nearly always ended up being losing ones.

3. Table selection. I 6 table 6Max and if I am still at the same tables half an hour later they must be really good tables but most of the time I am dropping tables and finding better ones on average every 15mins. If there is a fish on my immediate left and 4 regulars than there will always be a better table available. It's 50NL after all.