Worth noting that at this time of year a serious leaf fall and subsequent decomposing leaves on the bottom will drastically affect the oxygen levels in the water. If you have a lake where there is a serious leaf fall in one area, or if the wind is blowing the leaves into a bay, or to one end for example, then fishing away from this area may help.
There are always exceptions of course, if there are fish showing in leafy areas obviously don't ignore them, and if the whole lake bed is covered in leaves then it won't help, but if there are no signs and the bed under your favourite tree is thick with leaves, I might consider trying somewhere else.