Gather a large feather, a sharp knife or pen knife, sandpaper, and ink
Clean the feather and remove any loose fluff
Trim the feather shaft to a comfortable length
Harden the tip by briefly heating it in hot sand or warm water, then letting it dry
Cut the end of the shaft at an angle
Slice a narrow slit up the center of the tip
Shape the nib by trimming both sides of the point
Smooth the tip with fine sandpaper
Dip the quill into ink
Test the pen on paper
Recut and reshape the nib as needed