Ohr Somayach :: Rosh Hashana And Yom Kippur :: The Laws of Rosh Hashanah

There are two beginnings to the Jewish calendar year, Nissan and Tishrei - reflecting the dual nature of Jewish calendar - lunar and solar, respectively. Nissan is the month of the Exodus from Egypt and Tishrei is the month of the Creation.
All the months follow the phases of the moon, and the years are adjusted so that the festivals stay in their appropriate seasons.
There is a specific harmony and rhythm to the Festivals, which serve to blend the physical and spiritual worlds, and to join nature with the human life-cycle.
The festival of Rosh Hashanah lasts for two days, even in Israel where all other festivals are only one day.
Prohibition of Melacha (certain types of work). Exceptions - food preparation, carrying, transferring or increasing fire. (For more information see the Laws of Yom Tov.)
The obligations to honor and enjoy the Festival are fulfilled by preparations like bathing, haircuts, special (new) clothing and cleaning the house. A husband must buy new clothing or jewelry for his wife. Treats are given to the children.
The woman of the household lights candles before sunset of the first night and a half hour after sunset on the second night of Rosh Hashanah and recites blessings over the candles.
The festival is sanctified in words (Kiddush) over wine at the night and also during the day, before the meals.

Foods representing joy and blessing are eaten at the night meals, and prayers are recited for a good year using puns based on the names and nature of the foods (simanim) - fish head, carrots, pomegranate (lettuce, raisin, celery).

Two festive meals each day.
Guests! Maimonides - "One who celebrates but closes his door to the less fortunate is engaged in joy of the stomach and not joy of a mitzvah."
Special Greeting for the first night of Rosh Hashanah:

The commandment to hear the shofar blowing requires concsious intent to fulfill the mitzvah.
The shofar blower recites two blessings; the community must listen to the blessings and respond "Amen" to each one. (One should not say "Baruch hu uvaruch sh'mo" to these blessings.)
One should stand during the recitation of the blessings and for all of the shofar blasts.
It is forbidden to speak from the beginning of the first blessing until after the final shofar blast (at the end of Mussaf).