Learning to make good soup has been a lot of trial and error for me. When I started out I would make the rookie mistake of just throwing everything into a pot and covering it with water. Now I know you need to build a soup gradually, nurturing it along, adding each item at just the right moment to let the flavors layer onto each other for just the right amount of time.
My lentil soup recipe is very representative of this philosophy. When I started making lentil soup, it was – well – depressing. Brown and gloppy, and overwhelmingly lentil-y. Even when I added chopped ham it was far from inspiring. Then I discovered French green lentils, which helped tremendously. Then I discovered adding enough stock to let the lentils dance around in the bowl instead of binding into mush. Then the addition of noodles and chunks of spicy pork sausage crowned the rendition. I still vary the soup considerably, but I seldom veer from the basic formula. It works.
First, the broth. Every time I roast a chicken I make a simple stock from the carcass, and freeze it in variously sized containers. I will often just thaw a quart or so of stock, then add water to fill out the pot. Every bit of extra flavor helps, but don’t feel the need to use nothing but stock, especially if the other ingredients are assertive. Get the stock and any additional water warm and ready to go before you start cooking.