Back to the original question.
How flimsy are the coarse rods you have? Beach and rock fishing calls for something a bit beefier.
Rock fishing:
*Always check the tides and wear appropriate footwear, plenty of people die each year by getting cut off from the land by the tide or by slipping into the water on seaweed covered rock.
I certainly wouldn't recommend a beginner to rock fish at night.
A 2lb+ test curve carp rod would be fine, as would a heavy spinning rod.
I'm sure you're conversant with how to set up rigs and I'd aim to use a sliding float and fish a strip of mackerel on a long shanked, forged hook between the sizes of 4 - 1/0.
Set the distance between hook and float stopper to about 6ft to begin with (this may need adjusting dependant on the depth where the fish are. If you haven't caught anything after an hour, try adjusting it higher or lower, this will also depend on the height of the tide).
Use a fairly long hook trace too, this will give a more natural bait presentation. This method will not only cater for mackerel, but will cover a wide variety of species - Bass, Pollack, Wrasse (throw the Wrasse back mid you - terrible eating!)
Spinning and feathering can also be done from the rocks. When feathering, this is where you need to fling out a decent distance. Sometimes with an insufficiient rod, the mackerel can be tantalisingly out of reach. This when you wish you had a beachcaster.
You could also try a crab line or prawn net.
Beach fishing:
*Always use shockleader. For a 4oz weight I'd say use a 50lb test strain nylon two and a half times the length of the rod. This prevents 'crack-offs' whereby the line snaps under the strain of casting and could potentially fatally injure someone. Much to my annoyance I see people fishing on crowded beaches and not adopting this approach.
Several methods can be adopted but, if you're after mackies, feathering is the best way to go.
As said previously a 2lb+ TC carp rod 11ft+ (or better still a beachcaster 12ft+) capable of casting a 3 - 4ox weight is ideal.
A string of feathers, no need to be greedy here no more than 6 on a string.
Punch them out to the horizon. When the feathers hit the water, close the bail arm on the reel and count how many seconds it takes for the weight to hit bottom. Keep the line tight and the rod tip will spring back when this happens.
Start your retrieve by tightening up and swinging the rod in a big arc to your side (keeping the rod between your legs helps) and reeling in the slack quickly, whilst bring the rod tip back round to face the sea again. Repeat.
If your having no success, and this is where counting the feathers down to the bottom helps, try varying the times it takes to sink. If it takes 20 seconds to sink to the bottom, let it fall for 10 seconds. Try varying depths and speeds of retrieve until you find the fish.
This can be neccessary when fish are thin on the ground. If it's a feeding frenzy, just slap the feathers over the top of them and pull 'em through.
Upon catching the mackerel.
Unfortunately, every year I see numpty grockles pulling out dozens and dozens of fish. Why do they need that many? Twenty is enough for anyone and remember that you have to gut them all.
I also see these people rip the fish from the hooks and chuck them down in a pile on the beach in the baking sun. Mackerel are a pelagic species (same as tuna) and spoil very quickly. The act of chucking them on the beach to die also creates stress for the fish and when they go into shock, they produce toxins in the blood which again taints the flesh.
Best method is to remove them from the hook, hold them facing away from you and placing 2 fingers in the top of the mouth and snapping their heads back (the top of the head should touch its back). You point them facing away because sometimes you'll get break the main vein and get a squirt of blood coming out, you don't want that all over your clothes.
Bring an ice box with you and chuck them in there until you've finished fishing. That way you'll have the nicest tasting fish possible.
Hope that's a bit more constructive for you.