I have been pushing myself to learn new stuff recently - mainly more lead work. In the process I have noticed that I seem to go through phases of learning, I wondered if anyone goes through similar stages.
1) Start of basically trying to remember and play the early parts of a phrase
2) Get it really awkwardly, but committed enough to memory to learn the next phrase.
3) Go through the same, gradually tying sections together. Improving both (weirdly the earliest bits I learn never seem to improve faster than later ones, despite more practice time)
4) Reach a point where all sections are learned, but lack fluidity. Sometimes I forget the next note or phrase, other times I can choke completely.
5) Suddenly I can do it. This is the best bit.
I think stage 4 is probably - practice until you get it right and stage 5 is practice until you can't get it wrong.
The last song I had this with was Sylvia - it's not technically demanding, but a lot seems to happen. I think it was about 2 weeks to get to stage 5. I think this is when I realised I am not a quick learner!