The human ear can be a complicated object to model given its intricate folds and subtleties. Ears can actually give a lot of personality to your characters; tiny ears on a long face can make a person appear goofy, thick cauliflower ears on a hard face can add an extra level of detail to a rough character. In order to pull this off an understanding of the human ear is needed. I will show you the basic steps I take to create a human ear, which can later be translated to most realistic or stylized characters.
I commonly use the edge extrusion method to build my base models and game assets (Fig.01). This begins by creating a grid with no subdivisions, then grabbing an edge and duplicating it using Shift + Right Click > Extrude Edge and moving this new edge to a desired location. For the ear begin by building the shape of the outer edge, curving it into the center of the ear and to the tip of the lobe.
Once that shape is blocked in, select most of the edges on both sides of the newly created strip and duplicate and extrude them inwards to create the anatomical part of the ear known as the helix. Make sure to leave enough open edges to begin building the ear canal and the bulk of the lobe (Fig.02).
Select two edges from the tip of the lobe and the end of the helix, press Shift + Right click > Bridge. This will add a few subdivisions that will eventually become the tragus and will, in theory, connect the ear to the head. Then create the basic curve using edge extrusion; this will be the foundation for the antihelix (Fig.03).
The next step is to fill in the canal section, creating a rim which will eventually expand into the antihelix and antihelical. Do this by closing off the antihelix inner rim and extruding the edges inwards. I try to let the helix melt into the canal as much as possible, leaving the hard edge more towards the helix as it comes out of the ear (Fig.04).