Composition basics

Any good and quick pointers when it comes to composition? I'll be
shooting a lot of architecture (mostly modern skyscrapers and other
buildings, but also some old architecture), landscapes (city and
nature) as well as daily life (if I dare come close enough to point a
camera in their faces ;-)

So far I've picked up a few things along the way which I try to keep in
mind when shooting:

- Ask yourself what you want to convey to the viewer. Focus on that
subject instead of trying to cram everything into the shot all at once.

-If the same scene has many interesting subjects, rather do one shot
for each of them close-up instead of an "overview" shot far away which
doesn't really focus on anything.
- Avoid distractions (a dark subject upon a dark tree etc.). Keep it
simple.
- When shooting moving subjects (a car etc.) leave some empty
"breathing space" in front of the subject, in the direction it's going.
- don't put your subject smack in the middle of the shot, but a little
to the left, right, up or down. That makes the whole picture more
interesting and "artistic"

Anything more to add to this list?