On the ground or in a treestand?
A buck or doe?
How big?
Is it running towards me, away from me, broadside, etc?
Compound, traditional, or cross bow?
How fast is it running(ie flat out, slowly sneaking, bounding, trot)
What's the distance?
Fixed broadhead or mechanical?
Have I practiced shooting moving targets with my bow(like a target stuck inside a small tire or a tennis ball on a string that pendulums in front of my target)?
Public land or private?
Do I know the land well?
Ever seen the movie Phenomenon ?