These are some teachings on eating maryada that I learnt from elders, in vadiayala, and Granths. I hope to properly implement them as well and hopefully they are useful to others here too ЁЯЩП.
1. Always cover your head while eating and remember Guru Mahraj before eating. This is mentioned in Rehatnamay as well.
2. To not speak much or unnecessarily while eating. This was heavily emphasized to us while we were studying in vadiayala in Punjab. This is mainly because when we talk, we don’t chew the food properly. Also to show respect and increase focus on the food.
3. Once you have taken your food, do not leave your food unattended. If you need something request someone nearby to get it for you.
4. Keep your focus on the food you’re eating.
5. Never refuse someone in need of food, try your best to get it for them. Guru Gobind Singh Ji tested their Sikhs in which Bhai Nand Lal passed when all others refused food to Mahraj disguised as a poor man.
Guru Amar Das Ji also give this updesh (as recorded in Gur Partap Suraj Parkash, Raas 1, Adhyai 39) to Bhai Lalo ji, Bhai Durga ji, and Bhai Jivanda ji mentioning that the best type of donation is food and to never say no to a hungry person.
6. Do not flaunt or show off your food in public. Food is one of the four things to be kept gupt.
7. Another useful tips is to listen to Gurbani /kirtan or katha while cooking and eating as it nourishes your food making it Amrit bhojan.
8. Try making it a practice to read this Salok before eating so that the food you eat doesn’t produce vices in yourself.
9. It’s also important to note that who cooks and how our food is cooked affects us because of the energy/vibes. If on some day, your mind is not being able to focus in meditation as usual or is not at peace for no particular reason, it could be because of your food source. Before Sri Guru Amar Das Ji met Guru Angad Dev ji, they met a Sadhu who once ate in their house. On leaving, when the sadhu realised that Guru ji at the time was without a Guru, the Sadhu became angry and told Guru ji that, by eating with him, he the sadhu had lost all his spiritual wealth that he earned after years of meditation. Guru Ji got very sad after this incident & was even more determined to find a Guru. This factors are the reason why saints are usually particular who they eat from and what they eat because it affects their meditation.
10. If you have suspicion on the food you’re going to eat and have no other choice. Recite Mool Mantar and “Tav Parsad Sarab Bharam Ka Naas”. This practice is said to be given by Kalgidhar Patshah to Singhs at Machiwara when kirphan bhet was done for the food given by Muslims when they brought Maharaj on palanquin disguised as Uch da Peer.
11. Wash your hands before eating. 
12. Avoid eating before doing Japji Sahib and Rehras Sahib.
