Here are a few general principles:
- start by sauteing onions in a bit of oil
- add other vegetables in the order of slowest to cook first--that means that carrots before squash and squash before cabbage
- cover and stir periodically
- when they're almost soft enough to eat easily, turn off the heat, and let them finish cooking. You can cover the pot with a towel, so the heat doesn't leave too quickly, and yes, keep the cover on.
- Of course you can use garlic and herbs, fresh or dried and other seasonings. Miso is good, too.
- I generally don't reheat them, and yes, they can be eaten cold.