This may be a little difficult to follow at this point because I’m working all the way around the hand. What I’m doing here is simply cutting edge loops around the hand as I described before. Some times I may redirect edges that are already there for spacing sake.
Here I’ve decided to take one of the loops around across the webbing of the thumb. Remember, this isn’t an exact science. This is a general pattern I follow. But every time I model a hand I’m still trying to figure out where to place these new edges I’m cutting.
Here I’m taking the edges going down the thumb and they will travel across the palm, around the back side of the hand, back around the thumb and up and over the fingers.
On this particular model I’ve diced I need some more geometry in that space between the finger and the thumb that I have selected so I’m going to edge loop split it. Part of getting a smooth model that deforms well is trying to get your faces a generally uniformed size. Meaning that I usually try to get the faces roughly the same size for a given area. Again, this is just a guide and not a rule.