Write with your pen by holding your pen in the most comfortable position for your writing style. Analyze what side of the nib should be shorn into an oblique shape. Generally, right-handed writers sheer the left side of the nib while left-handed writers sheer the right side of the nib.
Lay a sheet of 1000-grit sandpaper on a flat surface. Pull the pen across the paper at an acute angle so as to sand the side of the nib that will become shaped down. Inspect the nib under magnification to make sure that only one side of the nib hood is being sanded.
Stroke the pen forward and backward on the sandpaper until you have formed a 30-degree angle with the side of the nib. Inspect the nib under magnification to ensure that the angle forms a straight, flush surface.
Run the pen over a finer grit of sandpaper until any burrs have been smoothed out. After you have run the nib over extremely fine sandpaper or polishing cloth, test the pen's writing on a pad of paper.
Repeat the shaping process, starting at 1000 grit, to work on any problem areas that cause rough writing. Many calligraphers round the lower corner of the nib to help it flow more smoothly.
Finalize your nib by writing in circles and eights over a fine polishing cloth or paper.