Here, with 'isolate select' i can easily continue adding details to the areas between the fingers.
Make the third wrinkle where the finger meets the palm.
Continue at Level 2, forming knuckles and other basic features on the hand.
A typical detail, drag more points like shown in the picture to add character to the thumb area.
So, after some point moving the first finger starts to look like a finger. remember that you can go up
to Level1 or even at Base mesh for making gross transforms.
All in all, we haven't been deeper than Level3 in this tutorial, and we have gotten a nice topology.
Thing will go wrong, sometimes the model will crap up, i have seen level 4 or 5 point going haywire all of a sudden.
Let's look at some problems
Fixing errors