Just get a shrimp, grub or fish style soft plastic.
In some sort of natural color i don't think specific color matters to much.
walk along foreshores casting as you go and concentrate your efforts on jetties, rockwalls moorings, dropoffs and weedbeds as has been said, any bit off structure really
another thing is check out if there are bait fish, prawns in the water and try to imitate them with a lure
if you are using grub or shrimp styles you'll encounter some good bycatch like bream
if you fishing around 1 -2metres of water 1/8 or 1/2th as has been said is the go
also they are expensive but soft vibes are great
also make sure you slow your retrieve down in winter
enjoy and good luck