General tips
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.
Buy Local Food : The most local food of all comes from your own garden. Plant a new garden, enlarge the one you already have, or extend your growing season by using row covers and cloches.
Buy Organic Foods : Organic food helps protect the planet.
Organic farming ensures that bio-diversity remains available in the foods we eat and the wildlife that live on the farms.
Fruits and vegetables are naturally available in 100's of varieties. Commercial growing limits the variety of each food available by mass producing only a handful. Many species of birds, insects and other animals are affected by the chemicals and farming conditions used in growing commercial foods.
Organic farms grow a mix of crops and promote a balanced ecosystem including insects that protect crops from pests and worms and other micro-organisms which fertilize the soil.