A few that I would offer:

A) Proportions are critical - not having too long a tail or too short for example.
B) Use good materials and tools
C) Tie often to keep your capabilities sharp - I try to tie a few times per week instead of a jam session the night before a big trip.
D) Get good at a few patterns instead of diving in to a complicated jig with 48 materials and 97 steps

Good post.