The ONE Thing to Always Do When Baking Cakes

I recently took up baking and cooking, and am trying to be more adventurous in the kitchen. The Food Network is now one of my most-watched channels, and Ree Drummond and Giada DeLaurentiis are now my kitchen role models (judge as you wish).
A couple weeks ago, an episode of Giada at Home showed a delicious-looking lemon bundt cake with chocolate glaze. I immediately thought my dad would like it, especially if I substituted orange for lemon. So when I got back to Pennsylvania last weekend, I decided I'd make an orange bundt cake with chocolate glaze for my dad, as an early Father's Day treat (since I won't know if I'll be able to spend that time with my parents). 
I prepared the cake according to the recipe, and did everything right. Except for one thing:

I greased the bundt pan with shortening, but I forgot to flour it, too. And I didn't realize it until I'd already put the cake in the oven and it had 10 minutes left to bake. Big oops and hanging my head in shame. 
Fortunately my cake stayed in one piece for the most part, and I only had a few craters on top when I popped it out of the pan. But that was okay - I covered those right up with the chocolate glaze.

So the moral of the story here is: Always remember to flour your cake pans. Shortening alone doesn't always do the trick, and you can't always cover it up with glaze! Also, maybe next time I'll stick with semi-sweet chocolate instead of bittersweet. I'm still learning, right?
Have you ever made a kitchen faux-pas? What was it and how did you cover it up?