Lots of good tips here.
Personally some things I've learned:
Write down your planned recipe and procedure on one column on a notebook (even if you do most everything online.) write the actual numbers and so forth on the second column, to make sure you have everything.
set out all your equipment beforehand, make sure it's clean and sanitized long before you need it.
Ditto ingredients. Make sure your grains / extract are what you want, and in the amounts you want. Hop additions, if it's not even amounts for the packaging, weigh them out before you need them as well (during mash or waiting for things to boil is a good time)
WEar long pants and closed-toe shoes - wort and burners are hot.
Clean what you can as you go. if you're all-grain, you can start while the wort is coming to a boil or after the 60-min addition, cleaning out your mash tun and so forth.
I personally do not like to drink while I have open flames - too much to possibly go wrong, and forgetting steps. I don't pop the first one until the wort is in the fermenter.
Make sure your yeast is ready to go - I set it out when I start the brewday.