Things I've learned so far:
-always, always test your candy thermometer to see if it's accurate before using it.
-don't mix your salad and salad dressing way in advance thinking that it will put you ahead of the game.
-when baking, set your timer five minutes before the shortest recommended baking time and check on your food. It's always easier to add more time to undercooked food than to subtract time after you've burned something. (Unless, of course, you happen to have a handy-dandy time-turner like Hermione Granger, which I do not.)
-never lift a bowl of something off a pot of hot water to check if the water is still hot. Steam burns!!
-it's better to use a too-big pot than a too-small one. One that's just-right is best, but we can't always be so lucky.
-store-bought prepared food products are not always the devil.
-something may look hideous but also taste great.