Baking some of the vegetables before boiling makes a strong broth that goes a long way. I suggest you use it sparingly in recipes, probably half or two-thirds of the amount specified. Taste and decide if you need to add more broth or just water.
The trimmings of parsley and other herbs will add flavor to your stock. If you have freezer space, keep them in zip-top bags to use for your next stock. Adding seaweed makes the broth even more intense