Well again, it all depends on the strain of mushroom.
If you’re looking for Cubensis ect, its pastures, medows and fields; Wherever livestock excrete waste. They do propagate in the forest but to a much lesser extent that you probably wont find any, no matter how hard you look. Unless of course there’s a horse riding trail through this particular woodland.
Otherwise, strait after rain, or if it hasn’t rained before this point wait for the second or third shower to pass before you start your hunt. If looking for wood loving species; anywhere where there have been woodchips spread previously (they can’t be freshly laid) sloping regions with sandy, nutrient rich soil with direct cover from other plant species and shade.
Any more technical and specific information can all be found freely on the net. Start at erowid and work your way down the chain until you have sufficient knowledge to start your search. And again, it has to be cold for wood lovers; not so much for Cubensis and the ones which grow on dung, if at all.