I like Lake Washington a lot, and regularly dock-fish it for perch. My favorite is at Juanita; its a big u shaped dock with some nice water. Even the swimming area produces. Luther Burbank usually has some nice perch (fish the small dock that you have to hike to) and I caught a 4-pound smallie once while perch fishing! Occasionally, the Kirkland docks and Seward Park dock are good, but focus on the first two. What i usually use is the good ol bobber and worm fished close to the bottom, but i have caught smallies and even perch on spinners. Sometimes I get a wild hair and bust out the fly rod (which I usually save for trout and salmon) and catch a few perch on Hares Ears. Good Luck.