Before you go

Learn from a person, not just a book or appJoin a local mycological society foray or take a class before eating anything you find on your own.
Pick 3–5 target species to learn deeply this seasonDon't try to learn "all mushrooms"; focus on a handful with no dangerous look-alikes in your region.
Buy one solid regional field guideApps alone aren't reliable enough for edibility calls.
Check the land's foraging rules before you pick if conditionalMany state parks ban foraging entirely, and national forests often require a free personal-use permit.
Pack the right kitA basket or mesh bag (not a plastic bag, which turns mushrooms to mush and destroys ID features), a knife, a brush, wax paper for wrapping, and paper bags for separating species.

While you're identifying

Never rely on a single feature or a phone-app photo ID to decide edibilityConfirm every specimen with multiple physical checks: cap, gills/pores, stem, spore print, smell, and habitat/tree association.
Dig up the whole mushroom, don't cut the stemThe base (is there a cup? a bulb? volva?) is often the key feature that separates deadly Amanitas from safe look-alikes.
Take a spore print of anything you're unsure aboutLay the cap gill-side-down on paper (half white, half black) for a few hours; spore color is a real diagnostic, not a guess.
Note what tree or plant it's growing near and on what substrateSoil, wood, dung — many species can only be told apart by this context.
Photograph the whole mushroom in place, plus a cut cross-section, before you pick itUseful if you need a second opinion later.
Keep each species in its own labeled bag or wax paperMixing species makes later ID (and cleanup after a mistake) much harder.
Throw out anything you can't confidently name to species"Probably fine" and "looks like X" are not identification.

Get a second, independent confirmation from an experienced forager or your local mycological societyFor your first hunts of a new species.
Rule out the deadly look-alikes for your target species by nameKnow specifically what kills people in your area (e.g., death cap, destroying angel, deadly Galerina) and how to tell them apart from what you picked.
Cook every wild mushroom thoroughlyHeat destroys some toxins and many species are only edible cooked; never taste-test raw as an ID method.
Eat only a small portion the first time you try a new species, and wait 24 hours before eating moreEven correctly-identified wild mushrooms can cause individual reactions.
Save a raw, uncooked sample of anything you eat in the fridge for at least a dayLabeled, with a photo — this is what poison control needs if something goes wrong.
Skip the alcohol with your mealSome mushrooms that are otherwise fine cause a nasty reaction combined with alcohol for a couple of days after eating them.

Call Poison Control (in the US: 1-800-222-1222) immediately for any suspected mushroom poisoningDon't wait for symptoms to get bad.
Get to a hospital right away even if symptoms seem mild or delayedThe most dangerous poisonings often don't show symptoms for many hours, which people wrongly take as reassurance. With amatoxin-containing species, symptoms such as nausea, vomiting, severe abdominal pain, and diarrhea typically appear within 6–24 hours after ingestion, by which point real organ damage can already be underway.
Bring the leftover raw sample and any photos with you to the ERA history of eating foraged mushrooms and gastrointestinal symptoms like cramping abdominal pain, nausea, vomiting, or watery diarrhea, usually 24-48 hours after the meal, is exactly what doctors use to diagnose amatoxin poisoning quickly.
Don't assume you're in the clear after symptoms passAmatoxin poisoning happens in three phases, with the first phase involving delayed abdominal pain, nausea, vomiting, and diarrhea that often starts more than 6 hours after ingestion, followed by a deceptive "quiet" phase before organ failure can hit.