I use the guidelines below except where previous experience on the hole dictates otherwise:
Headwind/tailwind: Add or subtract half the wind (10 mph wind = add/subtract 5 yards). This includes 45 degree winds - they have the same effect on distance even though you instinctively want to take less wind into account. This does not apply to chips and pitches, and wind also has much more limited effect on punch shots.
Crosswind: The longer the shot the greater you need to compensate ie: more time in the air allows the wind to effect flight more. This all by feel for me.
Elevation: Generally, and again previous experience on the hole will dictate exactly how to approach this, I will add or subtract one yard for each 5 yards of elevation change.
All simple math that can be processed in your head in a couple of seconds.
Or follow Yappy's advice above and you'll probably be close too!