I've found that (depending on what lake you're in) the colors that work best for me are; spring green, rainbow, and flourescent orange (on the coastal lakes), chartreuse, spring green, corn, white and the red white and blue color(for the mountain lakes around Salem)
Now if you want to add to the scent of the bait, I've found that if you take the Berkley's trout attractant, and Mike's earthworm glo scent oil and mix them together with a 3 to 1 ration (3 parts trout attractant and 1 part earthworm oil), then dip your powerbait into it, it can make your day turn into a feeding frenzy. I've been sitting next to someone with the same exact set up as me minus the "dip" and caught my limit before they caught thier first fish.
If you're up in the Detroit Lake area, try either the white or the chartreuse power bait on a 4 lb test. Put your hook on and give yourself about a 36 inch to a 48 inch lead. I usually try to keep the bait no larger than the hook itself(about the size of a kidney bean). If you're up the Brightenbush forks, try finding a ledge or a drop off in the water, they will usually congregate there or swim along side the ledges for safety. If you can find the ledges, cast out about 15 to 20 feet past them and set the bail on your reel. Let your line drop till it hits the bottom and then reel in the slack line (Careful though, there's usually underwater plants and algea ready to snag your line if you don't reel in fast enough) If the fishing's on, well let's just say that I've had days up on the forks where I could barely set my pole down to grab a snack before some lil bugger was down nibblin at my bait. If you're on the dam, there are a ton of ways that will get you somethin nibblin. Usually just launching my bait out as far as I can get it and then letting it free fall back towards the dam.
Powerbait is just a simple bait that is easy for fishing enthusiasts of all ages to use. And if you're tryin to get a child or a first time fisher into it, take them up to Detroit and let em go for it. Chances are, they're gonna get somethin.
PS. If you head up for Detroit Lake on a weekend or a holiday, be prepared to rub elbows with about 100 other people trying to get thier limit.