Throw whatever vegetables which are growing old in your refrigerator into a stock pot and add 2 litres of water, rosemary leaves ( 1 sprig fresh or 1 tsp dried), bay leaves (2) and salt. These three vegs are essential though - tomatoes, onions and ginger. I usually put in cubed bell peppers, broccoli stems, celery stalks, cabbage or lettuce leaves. Let it boil and then simmer for an hour or so. Drain. I have not given actual quantity because I don't usually measure the amount of vegetables. But because I am putting in 2 litres of water, I must ensure that I do add in a substantial amount of vegetables. Otherwise, the stock will not have any flavor. Usually 2 litres of water with vegetables yields around 1 litre of stock after simmering for an hour.
Voila ! You now have the perfect base for flavoring rice, soups and many more delicious recipes...You can add lemongrass and kaffir lime leaves if your stock is particularly for chinese dishes. The flavor is indescribable. Nothing beats a homemade stock. Keeps for a month in the refrigerator if stored in a dry container.
The picture below shows the stock I made last weekend. It looks more like a clear soup.