Always carry a permanent marker. - Permanent Markers come in handy lots of times. At the circus, they are good for autographing programs. At parties, using them to draw eyes and mouths on balloon animals makes the animals come to life! And of course, they are a quick solution to fixing small make-up problems.
Permanent markers are great at those little touch ups that need to be done after a long day in make up. I always use a black one to go over any black make-up after I'm done powdering. I find it doesn't smudge as easily as using a make-up pencil.

Always give yourself plenty of time to get ready - I find that when I only allow for as much time as I usually need to get ready, something goes wrong. Either my nose is misplaced or my make-up doesn't look right or I forget something when rushing out the door. I always try to give myself about an extra 30 minutes, just in case something disastrous happens.