Catching walleye is not hard. You just need to find where they hang out at what times of day. The best times depend on lots of factors, but it isn't true that you can't do very well during daylight hours. In fact, I start most of my fishing trips about 10 AM through mid summer, and only fish early and late spring and fall. In murky or muddy waters, I have found that between 10 and 2 can often be the best time of the day to catch them. Many of my best days of fishing, I have started before sunrise, and not gotten a hit until 10, or 11, and they quit on me by 3.
Typically, I can find fish biteing somewhere at any time of the day, but as a rule of thumb, very early, and late are the best times, and despite what the books tell me, I don't catch crap between 11:00 PM and 4:00 AM. In the spring and fall, I go deep and fish off the bottom, maybe 25-35 ft during the bright hours in my favorite lakes, but many decent walleye waters don't get that deep in a lot of areas. Strangely, in the mid summer days, I find them suspended about 15-20 ft over 40-70 ft of water. I don't fish many shallow, fetureless lakes. I can find a fish or two, but without structure to conscentrate the fish, it's kind of hit or miss, and I loose a lot of tackle in the weeds.
More or less, the best way to fish walleye is to know your water, and the structure it contains. When I started, I couldn't find a a fish consistantly, but I talked to the fishermen, and got to know the water, but I havn't come home without catching a fish in years. They may have been 8 in long at times, but I cought them d***it!