I'll add a bit to the great advice already mentioned. You'll need a way to get down to them...either leaded line or better yet a downrigger. A slow troll is best around 1.2 mph. Most use shoepeg corn, maggots, or just pro-cure gel. Pink is probably the #1 color, but alot of that depends on the lake and day. Your best bet for a larger koke in that area of Washington is probably Roosevelt Lake. Lures like wedding rings, small spoons, apex's, hoochies, tubes, and lead jigs work good. The leader length depends on if the lure has any action of it's own. Most kokanee fishermen use dodgers, not only for attraction, but to give the lures some movement. Lures like the hoochies and tubes you'll want a leader of around 8-12" ...apex's, spoons, and wedding rings try 24-36". As far as getting the larger kokes, every lake is different. You might try trolling towards the bottom of the school you see on the fishfinder. I've read that larger ones hang deeper to protect the main school from predator fish, but chances are they are only going to a inch or two bigger. One thing to remember is the morning bite is usually good at most lakes...right around sunrise. You'll find that as the sun comes up, the kokes head down. Check out the past threads on here, lots of good information.