When I am like completley set on learning a solo(or I make something up that I think has potential) I get away from the tv, turn off my cell phone, load up the song and most likley some tabluture then turn off the internet so I have no distraction. Spend some time listening to it and warming up, try to get a little of the solo by ear then a little by tab then before I know it it's 7 hours later and I need some food. Haha well this has nothing to do with modes and types of scales but that is just my routine when I really wana learn something. A solo that I have been spending months trying to nail(and no where near yet) is Mr. Crowley, some of Rhoads very best playing!