I hate to say it, but the best way to get textures "more like real life" is to use photos of a "real model." That's how it's done. There is no humanly possible way (without going loony) to approach that type of detail (wrinkles, blotches, lines, prints, scarring, etc). Up close, skin has fine, semi-ordered details (lines, creases, wrinkles following muscle/bone/tendon/other dermal patterns...) and color variations (redness of knuckles, blues/purples/greens from blood vessels, concentrations of melanin...). I know that is not what you want to hear and not the easiest of possible solutions (getting someone to model can be either expensive or very difficult), but it is how the best high res human textures are made. I've tried the "make it in Photoshop" technique and it's great for quick basic textures or non-human textures, but cannot compare to the real thing, no matter how much noise is added or how many layers are used. When I finally decide to make my own character (someday, eventually ;), I will use a real model and already have someone in mind, although they don't know it yet (BWAHAHAHA...ugh).