I love to fish off rocks, one of my rods is a 9' 6" spinning rod with 8lb bs reel line (breaking strain) and one of 12lb on if it starts to get a bit snaggy, apart from spinners, I also put on bits of rag/lug worm, mussels, crab etc and leave this on the sea bed or below a float. You can have your bait under a float and different depths from a couple of feet to on the bottom. There are many sites for this information, WW, not enough hours in the day for me to explain, mate.
I've caught many a garfish 18" below my float cast out about 30 yards from the rocks on Anglesey and tons of wrasse right under me against the rocks but wrasse are very boney so I wouldn't eat them.