The oldies (and not so oldies in Dan's case) have it spot on here.
As a relative newbie to commercial flying (ust over 3000hrs) I guess I can remember the early days of blatting around the circuit in a PA28 learning the ropes.
Perhaps I've just been lucky but I believe I have had some good role models and instructors, from PPL through CPL, FI and finally commercial flying.
My various instructors all had their own little tricks and tips to ensure they kept out of trouble.
They included things many of you may recall. Check DI on line up, Time/Turn/Talk/FREDA at a waypoint, Red's Blue's Greens on short final, etc etc etc. Additionally they drummed those tips into my thick skull, along with the other obvious points such as the importance of MSA and maintaining SA etc.
When I instructed I tried to take the best of those tips and pass them onto my students, in the hope that it would help them.
Flying commercially I have taken and adapted them to form my own, personal SOP's that I run through at various flight phases (before start, line up, TOC, Cruise, TOD etc). Anal? Maybe. Over the top? Possibly. Saving my own butt? Absolutely.
We all make mistakes, and airline managers seem to think the best way to prevent re-occurance is a modified SOP or checklist. Maybe thats true, but it's killing off airmanship and resulting in pilots that believe if they blindly follow SOP and the checklist everything will be alright, and I'm afraid thats just not true.