I have a large garden but hate gardening so i use this as an excuse not to do too much! I live in a semi-rural area and the outer edges of the garden are left to shrubs, trees and brambles. Brambles are a pain but the birds and small furries love the berries in autumn and the bushes provide cover for loads of birds and hedgehogs. I suppose the answer would be don't mow the grass too low, and don't be too proud about having messy areas. Insects love things to crawl under, fallen branches can be wonderful for certain insects, plant shrubs which attract birds and butterflies, feed the birds and just enjoy it.