Don't throw away vegetable peelings like onion skins, carrot tops and skins, chard stalks, leek tops etc. Put them in a pan of cold water with a bayleaf and some peppercorns, bring to the boil and simmer for about an hour to make stock. Add chilli or herbs to taste. Use straight away or cool and fill into ice cube trays. Freeze solid, then unmold and store in plastic bags in the freezer, use when needed.
Don't add potato peelings, as you will end up with cloudy stock.