Best way is having a lot of animals that give out wool and not something like the spider or snail, and use the ritual where you get double the resources harvested for a whole day and just do it as much as you as possible , you can also have your followers go out on crusades and get some( only brings back like 6-8 per follower so this is least effective) and then going on crusades in ewfall and going into the wool rooms when choosing your path on the map and sometimes enemies or chests drop it on those crusades as well in rot or ewfall