When you eat or drink, it is obligatory upon you to say "In the name of God", and you shall take the food or drink with the right hand. When you finish you should say, "Praise be to God".
It is preferred that you should lick you hands before you rub it off. It is part of table manners that you should apportion one third of your stomach for food, one third of it for drink and the last third for breathing. When you eat with others you should eat what is in front of you. You must not take a morsel until you have finished with the previous one. You must not breath in the vessel when you drink. When you breathe you should take away the cup from your mouth. Then you bring it back if you like. You must not gulp water but sip it. You must, besides, chew your food well before swallowing it. Further, you must clean your mouth after eating. If you wash your hand after drinking broth or milk, it is proper. You should pick your teeth to remove the bits of food which stick in them. The Prophet - peace be upon him - has prohibited eating and drinking with the left hand. When you drink in turns, you pass the vessel to the person on your right. It is prohibited to blow with the mouth upon food, drink or a book. It is also prohibited to drink out of a gold or silver vessel. However, there is no harm in drinking while standing. It is not proper for a person who has eaten raw leek, garlic or onions, to enter a mosque. Moreover it is reprehensible to eat while reclining. It is reprehensible to start eating from the top of the 'tharid' (bread soaked in soup). It is prohibited while eating dates to eat two at a time. According to some views, this rule only applies when you are eating along with others. However, there is no harm in doing that when eating with your family or some people you are feeding. While eating dates and such like, there is no harm for you to pick the fruit you fancy.
Washing hands before eating is not part of the sunnah (tradition of the Prophet), except when they happen to be dirty. One must wash one's hands and mouth after eating broth, and must rinse ones mouth after drinking milk.
It is reprehensible to clean the hand with foodstuff or some leguminous plants, or with husk. But in respect of cleaning with husk, opinions differ.
You must honour invitations to wedding feasts, unless there happen to be some merriments or something clearly reprehensible. However it is up to you whether to eat or not. But Malik gives a dispensation for those wishing to remain behind if the crowd is too large.