I have to be honest; we just pretty much gave our garden back to nature. We don't use any insecticides, herbicides and stuff like that. We made a wood pile where hedge hogs can sleep, birds can make a nest (no cat can climb in there) and insects can hide. Over the years i started reading about and observe first hand how useful all kinds of 'weeds' are. So, i stopped weeding the dandelions and noticed how attractive they were to insects and certain birds munching on the seeds. Our ivy took over and it flowers right now. I learned ivy is incredibly important for insects, because it's one of the final flowering plants and bumble bees and bees can collect nectar to have energy to make it through the winter. I started realizing the importance of native plants, so when we added a pond, i exclusively went for native plants in and around the pond. We live in the suburbs, but if you watch our house you will notice how all birds fly to our garden. While most people around us have stony gardens with a non-native plant here and there, our garden is like a haven for all kinds of wildlife. I think i counted about 20 different species of birds. We have bats, we have a sparrow colony under our roof, and many birds eat, mate and nest in and around our garden. When i plant something - but i'm running out of space now - i decide on; is it native, how attractive is it for insects and birds, does it provide shelter (for instance thorns, so birds can nest in there without cats being able to reach them), things like that. If any neighbor would see our garden (it's completely enclosed), they would be appalled, but honestly; we love it. I even am a part of the ecosystem; birds know that they can ask me for help, so when they signal there is a cat nearby, i will chase them off (i love cats, but not in our garden). If there is a sparrow hawk, i even had a blackbird risking his life to point out to me where it was hiding, because he knew i would be able to chase him off. Which i did, only because the blackbird showed me where he was hidden. I've been handfeeding a dove for eight years. The first years he brought the chicks to us when they started flying and they literally crawled over our laps! In time he learned that this was not the smartest thing to do, because then the chicks would never want to leave. So, in time, he started to secretly come to us (with his mate), so that the chicks did not discover where their parents were eating.
This garden has taught me so much, it's wonderful :-)