The depth of your veins is genetic. The vein you are referring to is the cephalic vein. In some people it is very prominent (i.e. Ronnie) and in others is non-existant visually (see Cutler). Chances are, if you are seeing your superficial epigastric veins on your lower abdomen, then you are pretty low in BF, and if your cephalic vein isn't prominent now, it really never will be.