1- mentioning allah’s name. (saying: in the name of allah).
2- using the right hand.
3- eating from what is (placed) in front of the eater.
these sunnahs are gathered in this hadith: (o boy, mention allah’s name, use your right hand and eat from what is (placed) in front of you). narrated by muslim.
4- rubbing the bite, if it falls, and eating it: the hadith (if a bite falls from anyone of you, he should rub the dirt off it, then eat it…). narrated by muslim.
5- using three fingers in eating: (he (pbuh) used to eat using three fingers) narrated by muslim. this is what he (pbuh) often did and this is better, except when necessary.
6- the way one sits while eating: kneeling on his knees and the upper face of his feet, or extending the right leg and sitting on the left one, this is the preferable as stated by al-hafedh in “al-fat’h”.
And there are sunnahs after eating:
1- licking the dish and the fingers: the prophet (pbuh) ordered (us) to lick the fingers and the dish and said: (you do not know in which of them the blessing lies).
2-Praising allah after eating: (allah is satisfied with the slave, who eats a meal, then praises him for it), narrated by muslim. one of the prophet’s (pbuh) supplications after eating: (all praise is to allah, who has fed me and provided me with this without any strength or power on my part).
the fruit of this supplication: (all his precedent sins are forgiven), narrated by abu-dawoud, at-termithi, ibn-majah and al-havedh and al-albani said it is good.
* the total of sunnahs, which the muslim should keep when eating is not less than  sunnahs, supposing that he eats three meals per day and night, and this is what most people have. one may increase these sunnahs, if there are snacks between these three meals.