The bell was sounded, and I hurry to the request. So.
The trick to making fish stock is collection. Unlike meat stocks which can be made from items you can go and buy, if necessary, fish stock calls for garbage. Nobody is going to sell you shrimp tails etc. Old fashioned fishmongers would have done, but good luck finding them. So first you have to collect bits and pieces of fishy.........stuff.
It's not as bad as it sounds. Whenever you eat shrimp, throw the skins and tails (not the veins!) into a ziplock bag in the freezer. Whenever you eat whole fish, do the same with bones and heads. If you are lucky enough to have crab, save the shell. Any trimmings from any white fish (don't use oily fish) can be saved, except for entrails.
Break up bones and shells into small pieces and put it all in a pan, adding just enough water to cover. Cook this very gently, don't let it boil, and don't stir it. You want a clear stock, so as the scum rises up, skim it off. This process takes about an hour, so it makes sense to collect quite a lot and do this in large batches.
Once the scum process is finished, you can add (white) pepper, herbs and vegetables (onions/carrots/celery) as you would any stock, and a drop of white wine if you like, then let it simmer again until the vegetables have softened, about half an hour, skimming off any more scum which the veggies tend to cause. Then strain the whole thing. Cool, divide, and freeze what you don't need right away.
(N.B. I hope you guessed, you don't need to add salt to fish stock)
Now then. The herbs. If you look this recipe up in a book it will tell you to use bouquet garni. The modern way to buy these is little expensive teabag type jobbies. But if you go to an upmarket store where they sell more than one brand, LOOK CLOSELY. What's in there? I guarantee the number one ingredient will be parsley, because it's CHEAP. I don't know about you, but I resent paying that sort of money for dried parsley when I can get a 1/4 kilo drum of it for the same price!
Although it's a bit fiddly, it's fun to make a bouquet garni. You can use cheesecloth (buy it in the dollar store) or a coffee filter. Either way you'll also need string. Tie your herbs inside this, tight, tuck it under the solid items in your stock, and tie the other end to the pan handle. This will ensure your stock gets all the flavour but no bits.
So what goes in? Well in an ideal world, fresh herbs from your garden. But it's January so lets be realistic. You are probably adding dried herbs. Start with a bay leaf, some thyme, parsley, and then it's up to you. Despite what you've heard, bouquet garni is not a recipe written in stone. Any of the common kitchen herbs can be used, and you can experiment. I am particularly fond of chervil in mine. It doesn't have to "match the dish" because you add other herbs for that. The purpose is to bring out the fish flavour while adding aromatics to it.
Note: If you only have black pepper in the house, and it's in the form of whole peppercorns, put them INSIDE the bouquet garni. This avoids black spots in your fish stock. Personally I don't care if I have spots in my stock, but you may as well know this trick.