Make this your starting point... figure out what your 150 club is (150 after the ball stops, not how far you fly it) and work from there.
If it is your 7 iron, start there and go 1 club up/down for every 10 yards. So if you are 160 out you would use a 6 iron, 170 out a 5 iron, so on and so forth.
Also, any time you are playing an uphill shot, choose 1 more club than the distance. Anytime playing downhill, choose 1 less than the actual distance. If severely up/downhill... play 2 clubs more/less. Same for strong head/tail winds.
Lastly, always figure out the distance to the