"I've noticed that no matter whether they are barbarian lords, deranged wizards, mad scientists, or alien invaders, they always seem to make the same basic mistakes every single time. With that in mind, allow me to present..."
The Top 100 Things I'd Do If I Ever Became An Evil Overlord

some of the best are
- I will not gloat over my enemies predicament before killing them.
- Shooting is not too good for my enemies.
- My ventilation ducts will be too small to crawl through.
- The hero is not entitled to a last kiss, a last cigarette, or any other form of last request.

- When I've captured my adversary and he says, "Look, before you kill me, will you at least tell me what this is all about?" I'll say, "No." and shoot him. No, on second thought, I'll shoot him and then say "No."
- Despite its proven stress-relieving effect, I will not indulge in maniacal laughter. When so occupied, it's too easy to miss unexpected developments that a more attentive individual could adjust to accordingly.
- I will never build only one of anything important. All important systems will have redundant control panels and power supplies. For the same reason I will always carry at least two fully loaded weapons at all times.

you can find more here 100 things to do