It is mustahabb (liked, preferable) for the one who has made a sacrifice to not eat anything on that day before he eats from it, if this is possible, because of the hadeeth, “Let every man eat from his sacrifice.” (Classed as saheeh in Saheeh al-Jaami’, 5349). This eating should be after the Eid prayer and khutbah.
This is the opinion of the scholars, including ‘Ali, Ibn ‘Abbaas, Maalik, al-Shaafa’i, and others. The evidence for this is the hadeeth of Buraydah (may Allaah be pleased with him): “The Prophet (peace and blessings of Allaah be upon him) would not go out on the day of Fitr until he had eaten, and he would not eat on the day of Adha until he had slaughtered (his sacrifice).” (Al-Albaani said: its isnaad is saheeh. Al-Mishkaat, 1/452).

It is better for a person to slaughter the sacrifice himself, but if he does not, it is mustahabb for him to be present when it is slaughtered.

It is mustahaab to divide the meat into three: one third to be eaten, one third to be given as gifts and one third to be given in charity.
This was the opinion of Ibn Mas’ood and Ibn ‘Umar (may Allaah be pleased with them).

The scholars agreed that it is not permissible to sell anything from its meat, fat, or skin. In a saheeh hadeeth, the Prophet (peace and blessings of Allaah be upon him) said: “Whoever sells the skin of his qurban, there is no qurban for him (i.e., it is not counted as udhiyah).” (Classed as hasan in Saheeh al-Jaami’, 6118).

The butcher should not be given anything of it by way of reward or payment, because ‘Ali (may Allaah be pleased with him) said: “The Messenger of Allaah (peace and blessings of Allaah be upon him) commanded me to take care of the sacrifice and to give its meat, skin, and raiment ( covering used for protection ) in charity, and not to give anything of it to the butcher as a compensation. He said, ‘We will give him something from what we have.’” (Agreed upon). It was said that it is permissible to give the butcher something as a gift and that it is permissible to give some of it to a kaafir if he is poor or a relative or a neighbour, or in order to open his heart to Islam. (Fataawa al-Shaykh ‘Abd al-‘Azeez ibn Baaz).