1. Don't ever walk away from your kettle before the boil, I swear, every time I turned my back, the kettle boiled over.
2. Have a spare tank of propane around; more then likely, a propane tank will quit 20 minutes into a boil.
3. Pitch more yeast then you think you need for a lager, a 2000ml starter never worked for me. a 5000ml starter or freshly harvested cup of yeast slurry always does the trick.
4. Oxygenate your wort. the yeast and your taste buds will thank you.
5. Always use a sturdy secondary container for moving carboys; like a milk create. Eliminates a lot risk for using glass carboys. never had a issue using glass.
6. Pay Attention to your water profile; learn a little bit about water chemistry.
7. Control your fermentation temperatures.
8. keep your recipes simple. complexity is good, complicated is bad.