A few tips and tricks I've learned along the way (as well as the occasional warning!) Updated regularly.
For soft and chewy oatmeal cookies, try replacing half of the all-purpose flour called for in the recipe with cake flour. Also, be sure to pull cookies out of the oven a little before you think they're done.
Use a Sharpie to label spice containers on top of their covers and store them together in a wide, shallow container, like a brownie pan. This way, the little containers won't get lost in the cabinet and you won't have to pull each one out to find what you need.
Cut all the onions you'll need for multiple meals at once. If you know you're having three dishes that call for onions this week, cut up all the onions you'll need for all three. Keep the extras in the fridge, and save your tears for the next time you watch Bambi.
Freeze homemade breadcrumbs. I hate throwing away food, even the stale ends of bread. Instead of tossing leftover bread to the birds, I whirl it in the food processor, put the bread crumbs in a freezer bag, and store them in the freezer. Just scoop out what you need as you need it for meatloaf, meatballs, etc.
Elevate a glass of champagne by floating a few raspberries in the glass when you serve it.
Crank up almost any flavor with a bit of salt.