Use Foam clay and Silk Clay together
Foam Clay is related to Silk Clay, and the two materials supplement each other really well when you want to model. Actually the only difference between is the consistency. As the name entails is Silk Clay, silk-like, but because Foam Clay has a lot of polystyrene beads added the consistency becomes more grainy and sticks a lot better to other items than Silk Clay does. By using both types together you can illustrate smooth teeth and messy hair just as an example of the great synergy.