For hosts:
1. Don't be the diet police. Even if you're a doctor or a dietician, it's not your job as a host/ess to monitor the calorie, fat, cholesterol, or carb intake of your guests or give unsolicited advice about weight loss or gain. If you think someone is not eating healthy at your event, keep it to yourself. Also, don't let any of your guests act as the diet police either. If your guests are on restricted diets, don't monitor them to see that they are adhering to their diets. As distressing as it may be to find that they are not, it is ultimately not your business.
2. Do inquire of your guests about their dietary needs and preferences when inviting them, but don't feel that you need to be a short-order cook or tailor the entire menu to their needs. If your guests choose not to consume something you have offered, keep your disappointment to yourself. Don't urge them to eat or fret about not having something for them to eat-it is their choice not to eat. Respect that without fuss or melodrama.
3. Don't allow guests to dominate the conversation at the expense of other guests. If you see that other guests have tuned out because one or more of your guests have turned out to be really windy, step in and pull non-participating guests into the conversation. If your windy guests refuse to stop talking, ask them discreetly and quietly to shelve the subject and allow others to participate.
4. Don't allow the conversation to get really aggressive to the point that guests are looking uncomfortable. If it starts to get really heated, step in and ask your guests to ratchet down the volume and/or change the subject. Don't let anyone go on ranting.
5. If the conversation stalls out, be the person to get it restarted. Make sure all your guests are properly introduced. If you are aware that a topic of conversation is really uncomfortable for a guest, change the subject for that guest's benefit.
6. If the occasion is to be a potluck, indicate that at the time you extend the invitation. Otherwise, it is your duty to provide all the food/drinks to be served and the utensils, plates, cups, etc. with which they will be eaten at your own expense. Don't send your guests out to do your shopping for you.
7. While it is gracious of guests to offer to bring things, don't take them up on their offer unless they can realistically bring something you would like. And don't "expect" them to offer-if they don't do so, don't ask them to bring anything but themselves and good spirits. Graciously thank your guests for any host/ess gifts they bring, but don't expect them. However, you are not required to serve consumable host/ess gifts.
8. Don't delay the meal to wait for late guests. Provide a realistic arrival and starting time, and if this has to change before the event takes place, notify your guests. Serve the meal at the stated time. If you wish to offer prayers before or after the meal, don't pressure your guests, especially those who are atheists or of different religions, into participating and if the prayers are not of fixed wording, try not to be long-winded.
9. Set the table and make whatever other preparations are necessary before the stated arrival time for guests. Don't expect guests to assist you with setting up or with clean-up, but if they volunteer, feel free to allow them to assist (moderately).
10. If guests are assisting with setting up or with clean-up, remember, they're neither slaves nor hired help. Don't expect them to do all the work.
For guests:
1. If the host/ess hasn't indicated that the occasion is a potluck, don't bring any food or beverages with you that won't be served to other guests. Tend to your specialized dietary needs before or after the occasion, or very, very discreetly if you absolutely need to do so during the occasion. If that isn't possible, decline the invitation.
2. While it is gracious of guests to offer to bring things, don't do so if it isn't practical. A guest who makes such an offer that is accepted by the host/ess should be prepared to follow up.
3. Arrive on time, not late or early. If you know in advance that this isn't possible, let the host/ess know that. Apologize sincerely for your untimely arrival.
4. Unless the host/ess has indicated that you should go ahead and eat, wait for everyone to be served before you begin. If the host/ess wishes to say prayers before the meal begins, but you do not wish to participate, remain silent and do not eat until the prayer concludes. It is not necessary to leave the table, but do not indicate through speech or body language that you do not endorse the prayer. If you wish to pray before beginning to eat and no prayers are said, do so quietly and discreetly.
5. Do not comment about foods or drinks served that are not to your taste or do not meet your dietary needs-simply decline to consume them. Also, don't expect your hosts to act as short-order cooks. They are the ones who get to decide on the menu. They should inquire about your dietary needs when they extend the invitation to you, but in the event that they do not, keep them to yourself and eat whatever is served that you can.
6. It is not your job to act as anyone's diet police. Keep your opinions about veganism, free-range meat, or any other facet of nutrition or health to yourself.
7. It is a kindness to bring a host/ess gift, but if it is of a consumable nature (food or drink), do not expect the host/ess to serve it. If your host/s do not serve your offering, keep your disappointment to yourself.
8. Do not smoke without the host's permission-even then, it is best to do it out of doors.
9. Stay out of private areas-do not go into rooms with closed doors or open cabinets, closets, drawers, etc. without the express permission of the hosts, and do not handle anything they do not offer you, including their electronic devices.
10. Do not engage in private behavior at the occasion-save that for your own home or hotel room.