Shaping the Hand:

Work on the hand is a good time to have a first glance at the Transpose tool, which is a new feature in ZBrush that allows you to quickly position pose or deform your model. The hand, such as it is, is not very realistic. Fingers are too fine, are not spread enough. To use only standard sculpting brushes to correct it is not really going to give good results.

Ctrl + Click on the hand to hide all but the hand polygroup.
Go into Scale Mode.
Draw a topological mask to mask the all the hand, except a finger.

To create an action line, click on hand's surface and drag out the action line. The endpoints of the line will snap to whatever is under them. (To move an entire action line, drag the line itself to move it.)

Click and drag from the inside of the midpoint of the action towards an endpoint, to scale the finger.

- Go into Rotate Mode.
- Click on the Line's Endpoint, and rotate the Finger.
- Do the same for all the fingers and toes.

Symmetry :

In certain cases, the Topological mask works much better when the symmetry is not activated.

When you do not sculpt a mesh by using a symmetry, you can nevertheless symmetrize it afterward.

To do that, mask the zone of the model which you want to symmetrize. Select the Symmetry Axis In the Tool Deformation Palette, apply a Smart Resym. In case nothing is selected, the whole model is averaged.

Posing the Model:

Posing the whole model with the Transpose tool is really simple.
- Create a new 3d Layer, dedicated to the Posing, and go to the 2nd subdiv level. The deformations will be made more easily, when the model has few polygons.
- You will have to, as for fingers, mask the part which you do not want to deform, adjust the Mask smoothness with the MaskBlur and MaskSharpen tools, and create one Action Line, and use that to deform the model.
- To Blur the Mask, hold CTRL and Click on the model.
- To Sharpen the Mask hold CTRL + Alt, and Click on the model.
- During this phase you should not only pose the model, but also to re-sculpt it, to have anatomically correct muscular deformations, compressions, and skin folds.