Go slow. Don't run before you can walk. Make sure it's solid before you speed it up.
I know this. I should do anyway -I've just spent 2 weeks playing a fast piece unbelievably slowly. And I proved to myself that it works. Not only did I get to know the piece really well, I could play it consistently at a slow pace. So why then, instead of working the tempo back up in slow careful stages, did I speed it up unbelievably fast? Duh. Now it's back to making mistakes again😕 I don't honestly know why I think to myself "this is really going well, let's see how much better it sounds when played a lot faster." Or even more idiotic, "I made a couple of mistakes, let's see if they disappear if I double the speed." Honestly I really am my own worst enemy.
Thankfully I'm using the super slow method on a second piece, also with a big improvement in consistency. This time I've been more careful about increasing the tempo slowly. So far so good. I'm keeping my fingers crossed I can keep myself under control😂
In the meantime: for the Carcassi - it's back to v-e-r-y s-l-o-w.
