On the day before Yom Kippur, it is customary to rise early to perform the ceremony of kappores. Dawn is considered the best time since dawn is the time of divine mercy. For more information on the kappores ceremony see http://www.jewishmag.com/25mag/kapora/kapora.htm
The custom is to pray the afternoon service early, before the final meal. Many have the custom to ask their neighbor for “food”, (lekakh in Hebrew) meaning begging for a piece of honey cake. The reason is that if it had it been declared in heaven that the person was to become a beggar, through this request for “food”, the decree has become fulfilled and therefore it may be annulled.
There is also the custom of flagellation. Many have the custom to request their friend to give them a flogging. This is done with a leather belt. No, it is not done with any force or pain, but like the “food” begging, mentioned above, the purpose is that if a decree was made in heaven that would mean receiving flogging, we have already received the punishment and therefore can be annulled.
It is the custom to feast on the day before Yom Kippur. Feasting on this day for the sake of having strength to properly fast and pray on Yom Kippur is considered as one actually fasted on two days. Towards the evening we eat the final meal before the fast. It is the custom to dip our bread in honey as we do on Rosh Hashanah. We eat only food which is easily digested, such as fowl.
It is the custom not to eat fish at this meal. Fish is generally eaten earlier in the day. We try to eat those foods which do not generate bodily heat such garlic, eggs, etc. Many do not partake of very salty foods such as pickles etc. which can cause a desire to drink.
It is important to finish this meal before the actual sunset. In this manner we can add from the profane day to the Holy day. Hence we start our fast slightly earlier than the exact time necessary, showing that we welcome the Holy day of Yom Kippur with happiness.
Since Yom Kippur is a festival, it must be honored by wearing our Yom Tov clothing. Yet since it is connected with the day of Judgement, we refrain from wearing showy and gaudy clothing. We must dress as if we had to appear in a court of law before a judge, in a respectable and honorable manner. Women traditionally do not wear jewelry on this day. Men have the custom to wear a white kittle, the traditional garment in which men have been buried in. This is to arouse the solemn feeling necessary for proper prayer on this day.
Candles are lit in the house, just like on any Jewish festival. They must be lit before the sunset. In addition, some married couples have the practice of lighting a candle in the bedroom to remind them that cohabitation is forbidden on this day. In addition, the traditional Yartzit candle, the candle that is lit in memory of the deceased is lit. This candle burns for 25 hours.
It is traditional for parents to bless their children before they go to the synagogue, imploring G-d to grant their children a year of good life, health, prosperity and peace. Others go to distinguished rabbis to ask them for a blessing for the New Year.
Although men traditionally wear the large prayer shawl, the talit, only in the day; on Yom Kippur, the talit is worn also at night. It is put on before the night so that a blessing can also be made on it.
Yom Kippur is the Day of Atonement for sins. Those sins that are between man and G-d, are easily forgiven, but the sins between man and man, require some prior work. To attain forgiveness for these sins, we must ask the person to whom we have harmed for his forgiveness, not always an easy task. It has become the custom to contact friends and family before the great Day of Atonement to beseech them that if we have hurt or harmed them, will they forgive us. How much more so must we actually approach some one that we really harmed! Only if when those whom we have hurt or harmed have forgiven us, then will G-d forgive us too.
On Yom Kippur, five things are forbidden: eating, drinking, wearing shoes, anointing with oil, and having sexual intercourse. When washing, as when coming out from the toilet, we only wash the very minimum possible. If a person is ill, he should consult a Rabbi regarding his or her specific needs.
Many people have the custom to smell spices on Yom Kippur. Hence in many synagogues, spice boxes are passed around the synagogue. The smelling of these fragrant spices helps to give strength to the person. In addition we are able to make blessings to G-d which increases our merits.
On the conclusion of Yom Kippur, the shofar is again blown, indicating that the Holy day has come to an end. We eat and drink and rejoice. We are confident that G-d has heard and accepted our heart felt prayers. The custom on this night is to begin is some manner to build the Succah, in this manner we show to G-d our love and involvement with his commandments.