How high up was the hill?
Add 1 Yard to distance for every 3 ft in elevation
if the pin is 21ft UP, add 7 Yards to your distance.
What was your lie?
If you are in the rough, you need to hit harder.
20% rough? hit it 8 - 10% harder
40% rough - hit 15% harder
What was the wind doing.. (over 15y it wont matter much at all) but keep in mind you need to also add distance if the wind is against you.. etc
Once you have done all that math in your head, select the club.