If you want to try digging your own ragworm, then the best areas tend to be inestuaries amongst the mud and rocks.

Use a strong fork with long, thin prongs.

It's often the case, although not always, that the bigger worms burrow deeper than the smaller worms. If you observe commercial bait-diggers, you'll see that they often dig trenches for ragworm. If doing this, make sure that you keep an eye on the tide and that you have a friend with you. Ragworm tend to frequent the muddy parts of an estuary and that mud can be very scary if you get stuck in it!

From my own experience, I've found that ragworm seem to congregate together, so if you have a rough idea where the ragworm beds are in your area, it may be worth trying a few places about 10-feet apart until you start getting among them.

Keep your ragworms in a bucket with a little bit of water and, if you get the chance, clean them and add fresh sea water before you leave.