I have a yard on several levels in town but still manage a thriving wildlife area. It’s messy but I love it. I have a pond full of newts with blackberries, honeysuckle, rosemary and weeds providing a wild backdrop.
the bottom level has a compost heap and lots of old wood, sticks, moss, broken pots all to create wildlife homes. This year I finally got my masterplan sorted and put a row of troughs all along the wall at the bottom of the garden. These have foxgloves and marsh marigolds grown from seed gathered last year. Also daisies, carnations, sweet William, wallflowers, sweet peas, nasturtiums and random other spare plants.
I have 4 pots I use as water features. Filled from the pond and with various pond weed including mint. They have stones in for wildlife to escape. The birds drink from them and sometimes bathe too!
I grow all my main bedding plants in masses of troughs and just grow as much variety as possible.
I leave the weeds to grow in between paving slabs. In fact I spread seeds around with some. Butterflies love nettles and a buddlia bush. Cinnabar moths love the ragwort and return each year to lay eggs. We love watching the beautiful caterpillars grow!
in autumn I don’t tidy up. I leave it all for the wildlife. The birds rummage for worms and the birds find seeds on the dead plants.
I have house martins and sparrows nesting in my house and birds come for breakfast daily!
hope this gives you some ideas!