Once upon a time, if you looked in my pantry, you'd find 2 large bags of soup mix. Chicken flavored for my soup and onion soup mix for chicken, rice and spinach kugel.
Since marrying a food snob (I love you!), you will no longer find the chicken soup mix. Instead, you'll find bottles of home made stock in my freezer.
It usually starts with a turkey carcass or two I've saved from a big turkey dinner (several times a year I'll buy a whole turkey for either Shabbat or holiday meal... and Thanksgiving of course). The bones with a bit of meat still on them, and yes, it's okay that there's some of the sweet gravy still stuck to the bird.
Then it's veggies - scrubbed but not peeled carrots, onions, celery, zucchini, sweet potatoes, a great big bunch of dill and parsley. Whole cloves of garlic. If parsnip were affordable, that would go in too. Once I even added kohlrabi.
The truth is, almost any nutritious, and aromatic vegetable is great for stock. The limit is simply how big your pot is.
I add a bit of black pepper, but not salt. Since I have it cooking for a while, I don't want to add salt and then have it become overpowering. Plus, since I use it as a base and add water, veggies and chicken when I actually make soup, I can add the salt then.
Fill the pot with water and then I bring the whole thing to a boil and then let it simmer for at least an hour and half, to two hours. Then I let it cool and decant into large soda bottles (here in Israel they come in 1.5 liter sizes) and then freeze. Next time though I'll also make a few 1/2 liter sizes for when I want to use it when making rice or kasha varnishkas or something like that.