Well, considering I don't have any of those things, I may not be the best resource on this information, but my guess is the best way to get those things is to diet.
yup! separation is a combination of the shape of your muscle, which is determined genetically, the size of your muscle, which you get through training, and having low bodyfat, which you get through activity and diet.
Yes, Im sure that is the biggest part of it, but when I was in Texas, some guy's who competed use to show me separation excercises when they would be getting ready. I just forgot them. Oh well, thanks anyway. Bam