I fish for them every year on a lake in the Poconos, usually in the summer. One of the old timers up there who fishes for them with a fly rod told me years ago to use "anything that's white." White and also white/chartreuse clousers work well, foxy clousers have too for whatever reason, and white deceivers and other big saltwater flies work well as do things I've tied with white zonker strips and flash. Anything bright and flashy that's good sized and moving pretty steadily. I never use a wire tippet, typically use a straight 20 or 30 pound fluoro leader on an intermediate line. I've caught pickerel up to 25 inches and have only had a handful sever the line in the past umpteen years. Used my switch rod with a skagit line and ten feet of T-10 this past summer, also with success.
They do not seem leader shy but I did an half hearted experiment a couple summers ago. I had a spinning rod rigged for pike from a trip to Gananoque Lake in Canada, with a 12 inch wire leader. Used it in that lake for pickerel and had absolutely no action. I took the wire off and started getting takes immediately. Could just be a coincidence, have certainly cast for long stretches before getting takes in the past so who knows, but I avoid wire when targeting them in that lake.