I'm kinda in the Zen approach to brewing. I learned from a few bad brewing days to:
1) Pick a day to brew and clear my schedule on that day (no work, no friends, no distractions)
2) Formulate recipe 2-3 days before brewing, making sure every ingredient is accounted for
3) 2 days before make starter and put in fridge to settle
4) 1 day before brewing, run water through filter, measure out mash water and pre-fill kettles (containers), treat water (campden, mineral additions) crush grain, spread out everything I will need: pots, sanitizer, cleaning supplies, burners, hydrometers, hoses, etc. If I'm overnight mashing-begin the process
5) On brewday, wake up early and start heating mash water (if not overnight mashing)
6) Clean as you as you go and put things away that you don't need anymore
7) I know I'll probably get flamed for this but. Absolutely no alcohol consumption. A cloudy head leads to mistakes anything from missing OG values, contamination, broken equipment, injuries, etc.
Of course I only have maybe 2 handfuls of brews under my belt and I'm sure some brewers can brew while hosting a party, mowing their lawns, and swapping out a transmission at the same time while hitting their numbers and finishing in 3 hours flat. I'm not one of these brewers and I doubt that I'll ever be so I'll just take this approach.