There are 2 different methods of smoking ; Hot Smoking and Cold Smoking. But before we go though either, the first thing to do, once you've prepared your fillets, is to soak them in brine. A typical brine consists of : 4 litres of water, 500 ml salt, 250 ml brown sugar, 75 ml Lemon Juice. You can soak them for just 30 minutes but I generally leave them in the fridge, in the brine overnight. Once brined, spread them on grills to dry, they will have a thin translucent film on them known as a pellicule. To do a Hot Smoke, they need to be above the fire, hot smoking cooks the fish while its being smoked. Cold smoking doesn't cook the fish, only giving the smokey flavour. You don't have to spend a fortune on a smoker, mine is just an old stainless steel pedal bin, ideal for hot smoking. I build a wood/charcoal fire in the bottom first, when that has stopped flaming then I add hand fulls of DAMPENED oak chippings. You don't want the chippings to burst into flames as that will very quickly burn the fish. So grab a bottle of wine & keep your eye on it. You'll need to add more chippings from time to time. As soon as the oak smoke starts to fill the container, put the fish on the grill. I cover it with an upturned Wok, so the smoke is concentrated around the fish. Its done when the fillets are a nice dark colour and the fish is sizzling. Its over done when the fillets have shrunk to 2" long (Yes, i've accidentally done that:DOH With Cold Smoking, you'd need to build a separate chamber as a smoke box with a pipe coming from your fire box. Fillets are usually hung in the smoke box where they get the smokey taste but don't get cooked. I'd recommend hot smoking for fish as the cold smoking won't kill off any worm eggs that may be present. There are many different woods you can use for smoking, I use oak because I can get it free by the dumpy bag full. If the fire is still going when i've finished the fish then I often smoke slices of cheese while it dies down, keep your eye on those though, cheese melts.