I've collected Spitzkeglige Kahlköpfe (Psilocybe semilanceata) for several years, and send more then 100 people on a trip. So some advise from an old hippy, in random order:
Its easy to confuse Psilocybe semilanceata with Düngerling (Panaeolus papilionaceus), that is growing on same meadows, but at different times. Its less dangerous to collect magic mushrooms, then to collect mushrooms for food, because most mushrooms mimic a poisonous one. If you collect magic mushrooms and pick the wrong one, then you don't have a trip, but if you collect mushrooms for food, and pick the wrong one you become ill, and might even die. But still, always collect them with someone who knows them well, because else you might pick non magic light poison mushrooms first, think you need high dose to feel something, and next time you take a much to high dose, if you got the right ones.
Do not eat them when tired in the evening, but better at the morning before eating anything else. Do not drink or take other drugs same time. I prefer to put them into a yogurt or quark. Drink a tea afterwards, wait 10 minutes after eating them, and then eat as much as you can, because you need the power, and likely are not able to eat anything while on trip.
Always take them in a small group of friends you really trust, and one of the group should stay sober, just for the case one goes crazy. Agree beforehand that you care for each other, and that you do not send anybody into a hospital, because insane asylums makes everything worse. They will put people on hard drugs, so those people become asylum addicted. Be prepared that someone might need help after a trip. Those who went crazy will become sane within a week, if you care for them at a good place, e.g. a cottage in the rural, but they might become asylum addicted for decades, if they can get no other help then those who exploit them for health insurance money.
Be prepared to go outside. Walking miles is very common on a mushroom trip. The one who is sober must ensure that the group stays together and nobody gets lost. Being alone on a trip is a very bad setting. Do not walk through the city, but through nature, and avoid places where big crowds of people are, e.g. dance clubs or festivals. The sober guy is also the mule for water, and should ensure that everybody is drinking enough.
Mushrooms do not cause addiction, but they are an anti-drug. Everybody I know who collected mushrooms in my age stopped it at some time, including me. But never try to blow up your trip forever. Never add more mushrooms to am existing trip, neither because of impatience nor because you want to continue the "fun". The only cases I know of people who got locked in (drug induced psychosis) on a trip are those who eat several times within a few days, and those who went to an insane asylum, where the trip is treated with other even more dangerous drugs.
The main trip will be 4-6 hours, followed by an activity phase of an other 6-8 hours, followed by a vibrant phase of several days, where memories of the trip come up very vivid, and feelings are very different. The complete trip takes a week most often. So never take them more then once a month. And never more then 3 times a year. Mushrooms are not a party drug, they are a sharp tool to reshape your mind. Be prepared that memories of your trip will burn deep into your mind. A trip is a lesson you will never forget. So do not take them, if you have bad feelings, in a bad group, in a bad set or setting.
Magic mushrooms are called magic for a good reason. You might encounter things that can not be explained by science. Those magic comes often together with a horror trip. e.g. my worst horror trip was when I was walking through a part of the city where lots of drug and drunk people party, and a few of them had green faces. Each of them stuck me with a horror. And the horror became even worse over the next half year, as each of them died on an overdose of heroin.