First cut tree or leftover stump flush with ground. Some people prefer to leave a length of trunk to use as leverage to help pry up the root ball, but it was not applicable in this situation.
Clear area of debris and expose the soil around the stump.
Dig a trench along side of the stump deeper than the main rootball depth
Using a pick and axe, chop smalle roots and pry up the main root ball.
Finally, close up the hole and clean up the work by areta.