Put on the pants with the shoes you plan to wear
Fold the hem to the desired length
Pin the fold in place
Mark the hemline with chalk or fabric marker
Remove the pants
Measure and even out both legs
Cut off excess fabric if needed, leaving seam allowance
Fold the raw edge inward
Press the fold with an iron
Pin the hem securely
Sew the hem by hand or with a sewing machine
Remove pins
Press the finished hem again