First, be cock-sure in your own ability to do something as simple and straightforward as identifying mushroom species because of your innate ability to recall every minutia of the field guides and your astonishing powers of perception and attention to detail. Then analyze closely the cap shape, scales, the gill/teeth/ridges/pore patterns in the cap underside including shape, width, spacing, depth, and color, the ridges, and the stalk, including a partial veil and/or annulus. Proclaim confidently when you have determined with 100% assurance that you know precisely what species of mushroom you have in your hand, because you are a mushroom genius.

At that point you can take a few bites. If you end up needing a liver transplant, then you know it was toxic.