My own method is simply to eat those that /cannot/ be mistaken for a deadly poisonous species. This include all boletus (Boletus edulis, Boletus spp.) [my personal favourite, but avoid those that cut red or yellow -- they can give you an upset stomach], fairy ring champignons (Marasmius oreades), parasol mushrooms (Macrolepiota procera), blewits (Lepista nuda) and shaggy ink caps (Coprinus comatus). Those are the /only/ mushrooms I will gather and eat, unless I am accompanied by an expert mycologist.
** Phil.
--------
True story from a conference in Sobieszewo, Poland, in the early 1990s. The organisers learned that many of the foreign delegates were harvesting mushrooms, and were understandably concerned. During the opening session the next day, the Chairman made an announcement : "Ladies and gentlemen, it has come to our attention that some conference delegates are picking our local fungi. While we welcome this interest in our native species, we are concerned that those of you who do not come from countries where these fungi are found may accidentally pick and eat a poisonous species, perhaps even a deadly species. We therefore recommend that before eating any mushroom you have picked, /please/, have it properly identified by a Pole, or a Ukrainian, or a Russian, etc.". Applause followed. Then a gentleman spoke, in a pronounced foreign accent, from the back of the room : "Mr Chairman, your advice is necessary, but not sufficient. Before eating any mushroom they have picked, our guests should have it properly identified by an /elderly/ Pole, or an /elderly/ Ukrainian, or an /elderly/ Russian". Long, loud and sustained applause !