I have a rig that really gets perch. I rig up a small jig with a longer shank hook. Put the point through a minnow's mouth so the point comes out the belly. Put this rig about a foot below a big ounce and a half chrome sinker, then put a minnow on a bait holder hook a bit above that.
Drop this rig to the bottom and raise it a foot. The upside down minnow will stir the bottom trying to right itself, making a little stir in the mud. The top minnow will be lively as ever, and attract a good number of perch at the normal depth. The flasher is especially important in muddy water. If you're using a rod and reel setup you can just use the minnow on the jig with a spring bobber.
The bottom bait is effective when northerns cruise higher in the water column. When you use this rig, impart no action to the bottom bait by jus tlowering your rod tip a few inches and raising it back up. This essentially only moves the top minnow and the flasher.
And if you're feeling really squirrely, try this rig with a couple 3-5 inch shiners and go after pike in the shallows, with just the bottom bait though in around 3 feet. Got a 12 pounder two years ago on this rig.
