Well, for a start, these are not really that exotic. Fairly common, or so it says in the good book.
As to finding them....I just go down to woodland areas. Scrubby and not well maintained is best. Then it's just a question of rooting about in the undergrowth. I went tooled up. Knee pads and gloves, long sleeves, work trousers. Secateurs are a must. A fork is handy for lifting them up and apparently that is not frowned upon by the folk in the know. Also handy is a set of make-up brushes from your local Pound Store. Good for sweeping all the dirt and carp off them. A small reflector is very handy too.
I went looking for stinkhorns which were reported to be there on Sunday but by today they had gone over and were starting to liquify. Not good for photos.