|Get that down yer neck !
The most successful method by far has been trolling the lure in the edge whilst walking slowly along the towpath. This is how I almost landed a 2lb + perch the other day, and again at lunch today managed a small perch followed by a larger zander of 3lb or so.
The method is an excellent way of quickly locating the fish ( time being of the essence on a quicky lunch hour sessions) and over a few short weeks I have found the areas where I catch are proving to be consistent with fish caught on multiple visits, as opposed to other areas seemingly barren where no takes have been forthcoming. Interestingly I have only caught one fish with a standard cast and retrieve on this particular stretch, whilst trolling has had much more success landing the fish mentioned with a few missed strikes thrown in for good measure.
So far there are two fish holding areas I have located in a stretch less than half a mile. The water is always pretty murky and brown, not the worst I've ever seen, but with probably just less than a foot of visibility at best. There have been occasional boats coming and going stirring up the muck on most of my short half hour sessions, but this has not stopped me catching. In these conditions I expect the fish are probably sensing more than seeing, although even if you can't generally see the lure yourself from the surface I'm sure if it passes within a foot or so of a predatory fish it is a target on both levels. Big Hammer 3" lures have worked best so far with the ever reliable 2 " Kopyto's scoring well too. I think the colour is not too important but I seem always go for a bright one. More importantly is to select one that your have most confidence in. Dark lures should work in these conditions too but as I haven't got any at the moment I can't back that up with fact - I will have add some to my next lure order and see for myself.