General cooking tips
Buy Local Food : See if you can find out where your food has gone before it gets to your plate. You may be suprised by the results. Often it will make financial sense for companies to transport food enourmous distances by planes, boats and lorries. This dosn't take the environmental cost into account (which of course is likely to lead to greatly increased economic costs in the long term).
Oven Tips : Fan-forced ovens cost 35% less to run than a conventional electric oven.
Buy Local Food : ...but at the same time, figure out what makes sense. It is more energy efficient to raise lambs in New Zealand and ship them to the UK than to raise them in the UK, because New Zealand lamb farming is more energy efficient. It is also more energy efficient to buy produce raised in Spain, than produce that has to be grown in greenhouses in the UK. Baby steps require figuring out which things make sense and which don't.