I agree with Lonewolf and mnfisherman. I think the most important things to keep in mind is very late and vey early bite . It is pretty common knowledge that the hottest walleye bit in the summer is at Night, all night. However, in the winter it is probably the most productive and hour or two after the su goes down, and an hour or two before the sun goes up. I am not sying that you won't catch them overnight, cause you probably will, but using these times will maximize your productivity without waiting in the cold too long.
Also, concentrate on drop offs, especially after the ice gets thicker. I would probably not even fish water shallower than 22 ft in a lake for them. If you can find ledges, you have a good bet. Also, channels in the lake weather from a creek or whatever, will hold them by the ton too. Just be careful, cause you might get a catfish there to. Seriously!