I am just a beginner, so I hope I don't seem like too much of a "smarty pants" by offering a safety rule. This one comes naturally for me, precisely because I am a beginner and it actually might be just common sense:
"Do not attempt climbing when tired or in a hurry, this can greatly increase potential for mistakes".

I've had to rest a few days before attempting new climbing technique because I wore myself out. If I go out late in the day when I'm tired or still sore from climbing the day before I risk taking a "short cut" rather than doing the safest procedure.

My two cents.

TW