Birds need somewhere to perch and sing to claim their territory. So the first part of the answer lies in planting a tree or two. If you plant a tree that flowers, you'll also be offering them food of a natural sort, i.e. flower buds, nectar, berries. Then if it's twiggy and spiny enough, somewhere to nest out of reach of the local cats. DON'T KEEP FEEDING BIRDS! they need to teach their young to forage for the precise range of foods for which their beak and digestive tract were adapted. They don't have long to teach it and once lost the knowledge may not be easy to reintroduce. We know this from human behaviour experiments like table-manners vs fast food. These ghastly urban bird-feeders are wiping thousands of generations of parent-fledgeling interaction from the gene-pool and instead leaving the coming generations dependent on handouts. Birds 'see red' - no, they're pretty mellow, but their eyes respond to long-wave light and so a lot of trees put out red or orange berries to make use of their wings to spread the seed far and wide. Fast-growing trees like Elder, and spiny tall bushes like Pyracantha, make a good place to start creating perching (singing) + foraging + nesting habitat. Cotoneaster is a good one, get hold of a tall one called Cornubia for a corner spot, it's a beauty.