I've noticed more and more how much I don't really notice. I always used to have my head stuck in a book. It's only this year that I've actually started looking around me and I have noticed so much more. The way the bark peels from the trees in late Spring. The different amounts of birds. The many types of gardens and homes. I've also started doing a bit of minor research (mostly Wikipedia and Google) into some of the local areas. I've examined Google Earth views of my home city and tried to wrap my head around where everything is.
I live in what would be to Americans (and most other countries), a large country town, but which is a capital city in Australia. I've always considered it just the same old few streets but, really, when I look at it now I see so much more. There is so much you can learn about your home town or city. So many places that you won't see if you just whizz by in a car.
I've walked through Rundle Mall and paid attention to what I heard or smelled rather than what I saw. I've travelled the O'Bahn and noted how the River Torrens grows more shallow or deeper depending on the season, temperature, and recent rainfall. I've even noticed how what was green grass and weeds in winter became clover in early spring and is now this yellow reed-weeds that just blankets everything. How even the grasses seem to have died and it's not even all that hot or dry just yet! I've noticed how dark it gets and how quickly in winter and how much better it is in spring when I can get home and its still daylight.
I've noticed all kinds of things. These all help me as a writer and as a person. We spend so much time trying to figure out the right adjective or metaphor to describe something we've never seen, that we don't bother looking around us to take inspiration from things we can experience.
So, as a writing exercise, learn to look around you. You can learn so much more that way.