We'll start with a decimated female model to use as a guide. Your female model may vary. She's on her toes because she'll eventually be wearing high heels. At least that is the plan.
Now run, do not walk, to ShoeBuy! There you will find the perfect shoe to use as a reference. Oh, heck. Why not screen grab more than a few to take home with you? If you don't have Interweb access, you may have to asked a girlfriend, a sister, or a mom for one (or even a pair) of their shoes to model from. Simply tell them that it's for science.
First the shape of the insole is created using the Facet Tool. We have left some space between our insole object and the bottom of this left foot here so that it's easier to work on the object. Be sure to copy and paste your insole object before proceeding.
Then hold the CTRL key and drag the blue arrow downward. This will begin the creation of our sole.
And weld this piece of the sole to the insole.
Now select the facets highlight here in cyan and hold the CTRL key again while dragging the blue arrow downward again.
This will create the super high heel and super thick sole for us (what kind of shoe are they making us do?!). If your blue arrow is pointing upward like ours is, it simply means the polygon normals of your sole are inverted. This was caused by the weld we did earlier. It's really nothing to worry about. In the meantime, please remain in your seats.
For now, your shoe is probably looking something like this. But after dragging the blue arrow to the right, and then dragging down on the green arrow...
...it should look something like this.
Setting the size of the Y-axis to zero flattens out the bottom of the sole.
We decided to bring the highlighted edgeloop down some.
We couldn't resist anymore and just had to smooth this thing to see how it looks so far.
Ok, enough goofing around. Well, after some more stretching and scaling to give this soon-to-be-boot more shape and an even higher heel, we end up with this style. But before smoothing it again, we'll need to add these edgeloops (highlighted in cyan). The edgeloops placed extremely close to existing edgeloops are to help create creases on our model.
What are the chances are of you picking the same boot style to use for a reference as we did?
Hide the foot and select the insole facets and then copy them. This gives us a new object to begin modeling the upper of the shoe from.
Simplify the mesh by merging the edges that were close together like so.
Hide the rest of the shoe and select the outer edges of the insole. Then copy and ...
... paste the edges and hide the insole. You should have some polylines similar to these now.
And by drawing a curved profile along the edge of our insole outline ...
... we can save ourselves some time maybe by creating a sweep surface.
Our insole is then welded to the new construction of the upper.