A little off post, but what I do is change my jukebox directory every week, make a new folder of 25 tunes I haven't worked on in a while, and then just listen to that playlist for a couple of days before playing the melody on my trumpet/piano. I play those tunes over and over with lots of rest in between. When it pops out with no hesitation, THEN I start to work on other keys. Mac is right>You have to know that tune REALLY well before you can start playing around with it! It also helps to get your bel canto thing together (singing, even if your voice sucks, like mine!)

Good luck,
Ed