1. Have a Clear Goal
Determine skin type beforehand, and stick with it.
When creating realistic or at least plausible looking skin we need to decide on the type of skin, and it's conditions. Is the character's origin a weathered environment? is his skin very dry or wet? And what is his age, for instance. Reference is key when creating the appropriate look and feel.
2. Make Good Use of A Layer System, To Stay Flexible
When creating skin, be sure to put every step of sculpting the details in a separate layer.
For example a Main skin folds, Directionality , secondary folds , skin weight , and a organic breakup layer. This will give you more flexibility during the process. You can easily increase or decrease the intensity of specific layer, or repaint parts, and erase them with the morph brush, without affecting other progress that you made. In short, don't try to get what you want in one go, or pass. Many layers create the illusion of realistic looking plausible skin complexity.
Included here is an example file of a possible setup.
3. Variation is Key
A character or creature has many different skin areas, that are exposed to different elements and ranges of motion. The combination of all the different skin details helps to make it look realistic.
For instance around the eye, the skin can have a lot of folds and creases because of it's motion and age. But at the same time this part of the skin is fairly thin and soft because of it ,what will make the amount of small tertiary detail less in this area than some other areas that are dry and more exposed.
4. Add the Right Amount of Weight and Direction
No matter how good the placement and variety of the skin textures you sculpted are, if they lack any sort of weight it will just look like scratches on a model.
5. Sculpt as Much of the Main Skin Detail Placements by Hand
Use detail maps only for the very small , tertiary details. This will increase your skill immensely, and will make you think more about the overall texture and it's backstory. In the end this will give you a better overall result in terms of design, and it's foundation.
When going for 100% photo-real characters, alpha maps, and skin scan textures would still be the way to go.
We want to thank Ivo for providing these valuable tips. Be sure to check out his Gumroad for more insight, and use the code: discount to get 40% off!