I usually collect a bunch of them while going around and store them. But my biome tip is this:

Thistles grow near GreyDwarf Spawners, so if you mark them you'll know very easely where to find them.

Raspberries grow by the lots near/around those empty spaces in the meadows where you find oaks.

Now Blueberries and Mushrooms its tougher because theres no real pattern to them so you have to mark at least the BlueBerries if you dont store them while exploring. But i usually find BlueBerries in steep places.

That being said, the best strategy is to hoard them on early game while exploring and go storing them and making recipes when you have more than you can keep.