Techniques & Tackle:
The 3 different species of Mullet require different methods to catch them. .
Thick Lipped Mullet:
Main setup is 6lb mainline coupled to a 5lb Fluorocarbon hook-link, I will often go down to a 4lb hook-link when on the float setup.
Legering - I use a Pair of Drennan series 7 specialist Avon Quiver rods with a 1.5lb t/c and a 1.5oz Quiver tip section. I set up using a running leger with a 6-10" hook snood over the top of a 1oz weight. Ground-bait is really essential but doesn't need to be too complicated I use plain liquidized or mashed bread.
Float Fishing - This is the main method I use as it is very versatile, I am currently using a Preston Innovations 14ft float rod coupled to an Okuma Aventa Centre pin reel/Shimano fixed spool. I personally use a sliding waggler setup, with a 3 gram loaded crystal waggler.
For areas of fast flow I use a stick float/loafer with a bulk shot pattern, set-up at the depth I require.
Occasionally I will free-line bread but is not a method I use very often now.
Golden Grey Mullet:
I do not usually fish specifically for "Goldie's" but have caught a few whilst set up for Thick lips. I have caught them down in the water and off the surface on bread flake although this is not the usual method. The more preferred method for them is to leger small worms on a light paternoster type rig. More commonly they are found on the more open sandy/shingly beaches. Similar tackle like the leger set up for thick lips can be used
Thin Lipped Mullet:
I have not actively tried to fish for Thin lips but have had some take a bread bait intended for Thick lips, Thin lips are generally caught on a baited Mepps type spinner once the treble hook has been replaced with a short length of mono and a single small hook, a heavy float can be fitted in line above the spinner to increase the range of your cast if you find the fish further out. Harbour or smaller rag-worm are ideal but they must be mounted so the worm is straight on the hook. If not the Mullet will give the spinner no interest, the theory is that if the worm is not straight it will cause the rig to loop round in circles on the retrieve and the Mullet will simply ignore it. Tackle wise I would use my leger rods with the Avon tip and a fixed spool reel for casting purposes.
These are all basic methods that I use and have resulted in some very fine fish. You can over think and over complicate Mullet angling. I feel it's best to find something that works and stick with it just evolving it when required.
Someday's however no matter what you do they will simply not take a bait, at those times it may be better to move to different spot fish there for a while and possibly return later. The fish will quite often be more receptive to a bait.