I suppose if they are on the top, floating dog biscuits or bread. if they're not fished for much bread will be good, if they are feeding.
The secret of this type of fishing is to get them feeding confidently before you fish for them. It takes patience and care, just chucking bait at them is often enough on its own to spook them, so be carefull.
If its the sort of day where they will feed on top, try putting some bait in at various points along the cut and WATCH. Get a couple of fish feeding confidently and you'll have a much better chance of catching one. Avoid repeated casting its the kiss of death. You only need one good cast when they're feeding.
Use the wind/drift to drift your hookbait towards them if you can, rather than cast. There are lots of other ways/modifications to surface fishing.
Alternatively, what I sometimes do when i'm pole fishing is just put some sweetcorn down near a feature, overhanging bush etc., and lob a semi fixed rig over it with a bite alarm on and usually, sometime into the session Bingo, I have to drop my pole sharpish and pick up the carp rod.