My latest project is learning Satch's "Always With Me, Always With You" by ear. One of those tunes I always liked, but never learned. I thoguht it'd be a good challenge for my ear - not so hard I can't do it, but not so easy I can do it without some work..
For some of the faster sections I have to listen to the same tiny 1/2 second lick 50 times before I really hear it. What's been working is just getting ONE note (first, last, or one that's being held a bit longer) in my ear and building forward or backward from there. Also, just listening to the rhythm of the lick - get the rhythmic pattern without worrying about what the notes are. That's actually a better first step.
Spent more than a few minutes with the right hand on the mouse, clicking the 'start position' of a lick, with my left hand on the fretboard, trying to figure it out over and over (and over)...