I used to toss out onion skins and carrot tops without a second thought. Saving them in a freezer bag for stock cut my waste and added depth to simple rice dishes.
Read a food blog that swore by adding a splash of vinegar to the pot. It helps pull more flavor and minerals from the bones and scraps. Makes a big difference in the final taste.
Yeah, the "boiled water with bits" thing happens if you just simmer them plain. The trick nobody talks about is roasting the scraps first. Toss your onion skins, carrot ends, and even garlic paper on a sheet pan until they get some dark spots. That burnt bit adds a whole nutty, almost sweet flavor that plain boiling never gets you.