Worm baits fall into two groups Ragworms and lugworms. All are treat in much the same way, stick the hook in the tail end and thread up the line till you reach the desired size. A pennel rig should be used when fishing multiple worms.
RAGWORMS
Lots of species available all make good bait. The big one is the king rag Nereis virens reaching 40 cm in length. Paddle, rock and cat worms are similar in appearance and should not be ignored. Many species have jaws (nippers), these can give a very mild nip. Can be dug up or found under rocks. Cultured ragworm is readily available all year round from most bait suppliers. Do not freeze ragworms.
LUGWORMS
Two species are used as bait The common lugworm Arenicola marina which lives in sheltered sandy beaches in a U shaped burrow with a cast and hole at each end. And Black lug Arenicola defodiens (also called runnydown) is much larger and does not form a hole next to the cast. There can be a lot of local names for lugworms runnydown, yellowtails, blowlug etc. To dig up the common lugworm dig a trench and work along it filling it in as you go. This produces the greatest number of worms for the least effort and prevents the beach looking like the surface of the moon. Much is said baout the environmental impact of bait digging by anti-angling idiots. However it must be remembered that a single rough sea can strip an entire beach of lugworms and all its sub-sand organisms which I think puts my dozen worms in perspective. Do not dig around boat moorings for obvious reasons. A while back someone got into bother for bait digging in Duridge Bay (around the time vast quantities of sand were being removed for commercial purposes). Black lug have to be dug out individually, always handle with wet hands to prevent them busting.
Black lug can be frozen easily.
Pop them and squeeze the guts out.
Lie them straight on a couple of layers of newspaper.
Cover with a generous layer of salt for about 3 hours
Shake off the salt and repeat steps 2 and 3.
Shake off the salt and lie the worms one inch apart on a length of newspaper
Roll up the paper and freeze.
Frozen black lug is ok when you fancy a nights fishing and you've missed the bait shop but it can't beat fresh bait.