Here's what I've found that works at Laguna Lake. Trout: Berkeley Powerbait (Orange or Orange with Glitter), Mepps Spinners 1/16 oz. or 1/32 oz. (silver w/white feather), small grubs on a 1/16 or 1/32 oz. jighead (white, yellow, chartreuse, etc., with white being the top choice). Bass: I haven't done too much bass fishing there but have seen some nice ones (about 4 lbs. or so) being caught on a twin-bladed buzz bait (white) and surface poppers (clear). Catfish: Believe it or not, the Orange Berkeley Powerbait also catches the catfish (I've also caught Catfish at Clark Park in Buena Park on the Orange Powerbait), hot dogs, mealworms, nightcrawlers and chicken liver. Bluegill: Live mealworms, Berkeley Powerbait Honey Worms or live small red worms.
Where to buy: Sports Authority in Fullerton: The Powerbait, Mepps Spinners, small grubs and surface poppers and they used to carry the worms, but now I think maybe only nightcrawlers. I don't think they carry the Berkeley Honey Worms, but they do now stock small Powerbait baits for Bluegill. Petsmart in Fullerton (same shopping center as Sports Authority) is where you can get the mealworms and maybe even the small red worms. Angler's Marine in Anaheim is the only place I've seen the Twin Bladed Buzz Baits.
Also, it looks like both trout and catfish are being planted there this week (probably today) as you can see the planting schedule here: http://www.dfg.ca.gov/fish/Hatcheri...hCoast.asp
Keep in mind that for the Trout and Bluegill you need light line (I use 2 lb. test), so you can cast those small baits.
Hope this helps and good luck!!