When travelling during daylight hours I always try to get a window seat on my flight. Clear days are the best as the views are great. Here’s some from my last flight.
Adelaide, flying north. The scene is out to the sea, showing the port area with the entrance to the inner port. It’s possible to see the saltflats with water in them, the sea water evaporates and the salt is harvested. On the right is Adelaide's first airport the Parafield airfield now used for small aircraft as well as training.
Saying goodbye to Australia for a few weeks, crossing the coast at Western Australia, north of Broome.
Flying out of Singapore, the Singapore Strait. All the cargo boats waiting to be piloted through the strait.
Pretty sure this is Amsterdam, there's a curved area that works as central Amsterdam.
If you're sitting on the righthand side of the plane flying into Heathrow, generally you get some great views of central London. It's possible to play 'spot the landmark'.
Daytime flights, get a window seat, it's worth the hassle of climbing over people every time you want to get out of your seat!