Leave piles of leaves to provide shelter for hedgehogs.
Grow ivy up tree trunks - its flowers provide food for many insects and shelter for over-wintering butterflies.
Don't trim herbaceous plants in the autumn - they provide places for insects during the winter.
Ladybirds will nest in bundles of sticks tied together.
Fit bird boxes for different birds with different sized holes ranging from 25-32mm in diameter (1-1.25in).
Use hedges for boundaries instead of fences, and trim before March or after August to avoid nesting birds. Include holly and hawthorn to provide berries.
Ground beetles and centipedes can be encouraged by leaving some areas untidy to provide hiding places.
Earthworms will increase when you regularly mulch bare soil.
Allow nettles and weeds to develop in a restricted area, plant ground cover widely and cover vertical surfaces with climbers to add lots of food and habitats for beneficial insects.

Safety
Avoid using chemical herbicides, fungicides, pesticides or creosote in your garden. See Organic Gardening, Controlling Weeds and Pest Control for more tips on how to garden without them.

For more information, visit the Royal Society for the Protection of Birds (RSPB), the Wildlife Trust, and Royal Society for Nature Conservation (RSNC).