When ever I'm sittin around whittlin something small, someone always says something like, "that looks impossible". "You do that with a pocket knife"? I usually just respond by saying, "ya, it's not that hard". Seldom do I stop and think how lame that response is. But it's true! Let me try to explain why it's true.
First, when you whittle small you have way less wood to remove. In fact you must discipline yourself to remove only the thinnest slivers with each cut. A real wood carver friend, who is now deceased (Thomas Perrin) would say if your chips are larger than a grain of rice they're too large.
It doesn't take the hand strength to whittle small. This goes for the hand holding the piece as well as the knife.
There are however, a couple of things that must be considered. Your knife must have a thin well sharpened/honed blade. You must pay attention to the grain direction, and be prepared to reverse the direction of cuts many times.
You also need good eyes and good light. Good eyes can be achieved by magnifiers.
Another random plus to whittlin small is that it's a whole lot easier to throw away the blank if you make a miss cut.
Here's a set of Boxer earrings. These started as a well cut blank. I used only my pocket knife, followed by fine sand paper wrapped around a 1/8" dowel.