Know when to aim at the flag and when not to......and most of the time don't! That alone took 3-4 strokes off of my index and allowed me to get to a level that I never thought I would. It also tightened my score dispersion from round to round as I didn't seem to have the "blow up" holes as frequently. I haven't dug into Decade Golf but I think they do a masterful job of teaching this and why it's so important.