Answer: By doing the reverse of that which one's inclination would lead one to do. If you are inclined to eat, do not eat; if you are inclined to drink, do not drink; if you are inclined to be active, be still; if you are inclined to be still, be active; if you are inclined to speak, be silent. Eating is not a sin, but if you sometimes try how long you could do without eating, it would be good. Drinking is not a sin, but if you sometimes try how long you could do without drinking, it would be good. Sleeping is not a sin, but if you sometimes try how long you could do without sleeping, it would be good.