I avoid air conditioning as much as possible (if I am too hot I hang a damp sheet on my window to cool the room. If that's not enough, then I prefer the fan.)
I wrap my gifts in beautiful fabrics instead of paper packaging.
I maintain my car and check my tire pressure regularly.
I replace butter with olive oil for cooking.
I don't use disposable dishes when I eat outdoors.
I hunt down devices in standby, I install intelligent power strips.
I avoid using the microwave to thaw food.
I make my own Christmas decorations (origami, cotton, cut-outs) rather than buy them and I choose LED Christmas lights.
I set my fridge at 4° and my freezer at -18° to keep my food in optimal condition.
I opt for local tourism on a small scale, with locals or camping.
I replace one portion of red meat with one portion of white meat per week.
I use a lid to cook food and choose a pan size that fits the cooking plate.
I drink local (or even Brussels) beer.
I choose a green electricity supplier.
I place heat-reflecting panels behind my radiators.