I was trying to figure out how to model a hand with long fingernails.
I looked at this topic: https://blenderartists.org/forum/viewtopic.php?t=51243&highlight=fingernails, but the technique shown here wasn’t suitable for doing long fingernails, so I spent some time pondering how to model long fingernails on a hand.
I started with a hand modelled like the one in that thread.
I then pressed the “K” key for the "knife tool and selected “Loop Cut” to put a loop half-way through the hand from the side.
Then I went into the top view and selected the vertices for the thumb and the part of the hand that the thumb was connected to.
I then placed a knife loop cut through the thumb area.
I then went into “face” selection mode and selected the faces that are going to be used for the fingernails and pressed “E” for extrude and selected “Extrude Region”
Then I scaled the faces accordingly.
I then selected the faces for the fingernails and selected “Extrude Region” again.
Then I moved the top face of the fingernails downward a little bit using the transform gizmo.
Now, I then lengthened the fingernails using extrude again on the forward-facing faces. I also scaled the ends down a little but using the scale gizmo for each face one at a time.
I selected the top faces of the fingernail and extruded them and scaled them down a bit to give them a bit of a curve at the top.
Then I selected the end faces of the fingernails and moved them down using the transform gizmo to give them a little downard curve.
The same procedures were used to do the fingernail for the thumb.
Here’s the hand with the finished fingernails. I know the hand itself isn’t quite right yet. The hand needs some more editing to make it more anatomically correct.
I hope this tutorial is helpful to someone. 
