a few 'little' things I do which makes my gig setup go more smoothly:

1) color code cables and receptacles
2) keep a gig equip/sup inventory checklist
3) leave non essential items at home or in your vehicle
4) store & call up charts, event sched & annoucement notes on a digital device (ie: ipad, cell phone, etc) eliminating misplaced notes/paper and lyric/song sheets.
5) Keep duct handy for the unexpected