First Night: Say she'hecheyanu after saying leisheiv ba'sukka (in kiddush), since she'hecheyanu covers the sukka and the Jewish festival. 
Second Night: Say she'hecheyanu before leisheiv ba'sukka (since it only covers the Jewish festival itself).

Do not say she'hecheyanu when lighting candles or saying kiddush on the last two days of Passover outside of Eretz Yisrael or the last day of Passover in Eretz Yisrael.

Each of the four cups has a different role:

• First Cup: Kiddush to sanctify the holiday.
• Second Cup: Sanctifying the hagada.
• Third Cup: Sanctifying Birkat ha'mazon.
• Fourth Cup: Sanctifying Hallel.

To fulfill the commandment of havdala (or kiddush), the person making kiddush must drink at least 2 fl. oz. (59 ml) within 30 seconds from the kiddush cup. However, drinking at least 4 fl. oz. (119 ml--a revi'it) from the havdala cup within 30 seconds allows you to say bracha achrona.  
 

On Rosh Hashana, before eating the symbolic foods (simanim):

• Make kiddush,
• Wash your hands,
• Say ha'motzi, and
• Eat bread.

Then eat the symbolic foods (simanim), saying the appropriate blessings (borei pri ha'eitz, borei pri ha'adama) before eating the simanim.
 

There is no need to wash a clean wine glass before using it for kiddush.

 

You may say any blessing on a mitzva—such as kiddush, hallel, Torah—for another person, even if you have already fulfilled the mitzva for yourself, as long as that other person is required to do that mitzva.

If there is not enough wine or grape juice for Shabbat (or Jewish festival kiddush) and havdala:

• Set aside the first cup for havdala; then, if there is one more cup,
• Use it for the morning kiddush.
• See How To Do Shabbat Daytime Kiddush and How To Do Shabbat Evening Kiddush .

 

Kos pagum means either:

1. "Physically damaged or broken drinking utensil”: You may not use such a cup for kiddush l'chatchila. OR

2. Cup of wine, grape juice, or any beverage that has been drunk from.  This beverage may not be used for a kos shel bracha until at least a small amount more of some beverage has been added.

We are required to eat two meals on Jewish festivals, each preceded by kiddush, one in the evening and one in the morning. For both meals for each Jewish festival day (and all three meals on Shabbat), say ha'motzi over two complete loaves of bread, each of which is at least 1.3 fl. oz. in volume. 

Source of Saying Jewish Festival Kiddush
Some kiddushes are commanded by the Torah (d'oraita); the others are from Chazal (d'rabanan), as follows:
Kiddush d'Oraita

• First night of Jewish festivals
• Night of seventh day of Passover
• Night of Shmini Atzeret.

Kiddush d'Rabanan

• First day of Jewish festival
• Second night of Jewish festival
• Second day of Jewish festival
• Seventh day of Passover
• Eighth night of Passover
• Eighth day of Passover
• Shmini Atzeret day
• Night and day of Simchat Torah.

Source of Jewish Festival Kiddush Location
Saying Jewish festival kiddush at the place where you will eat your meal is a rabbinical (d'rabanan) enactment.
Jewish Festival Kiddush-Meal Quantities: Evening

• For evening kiddush for a first-night (d'oraita) Jewish festival, a minimum of 4 fl. oz. (119 ml) of wine must be blessed on and at least half must be drunk.
• For evening kiddush for a second-night (d'rabanan) Jewish festival, a minimum of 3.3 fl. oz. (99 ml) of wine must be blessed on and at least 2.0 fl. oz. must be drunk.
• For the evening meal, as on the first two Shabbat meals and for all required Jewish festival meals, a minimum of 1.9 fl. oz. (56 ml) of bread must be eaten within four minutes.

Eating Requirements for Jewish Festival Morning Kiddush
There are two separate eating requirements during the daytime. They may be combined (say/hear kiddush and start the main meal right away) but are often done separately (say/hear kiddush and then eat some light foods and beverages; the main meal is eaten later in the day).
Note Since eating and drinking requirements on all morning kiddushes (both Shabbat and Jewish festivals) are d'rabanan, the required beverage amount for morning kiddush is only 3.3 fl. oz. (99 ml) instead of the d'oraita 4 fl. oz. (119 ml) (which is required for kiddushes for Shabbat evening and all first-night Jewish festivals).

• Morning kiddush requires a halachically legal “meal” with these elements:
  • Blessing on a minimum of 3.3 fl. oz. (99 ml) of wine (or other beverage),
  • Someone's drinking at least half the beverage, followed by
  • Eating at least 1.3 fl. oz. (39 ml, or 1/6 cup) of some type of mezonot within four minutes. 
    Note If you drink at least 3.3 fl. oz. (99 ml) of wine within 30 seconds, you do not need to eat mezonot.
    Note You do not need to drink the wine or other kiddush beverage to fulfill “establishing a meal.” You may hear kiddush and then simply eat the required amount of bread or mezonot. This applies to Shabbat or Jewish festivals, evening or morning.
     

 

• The real meal (kovei'a se'uda) requires eating at least 1.9 fl. oz. (56 ml) of bread (or matza during Passover!) within four minutes. It must include enough food to satiate. 
  Note You can simultaneously fulfill the requirement to “establish a meal” and to “eat a meal” by eating one (the same) piece of bread.

The seder is the only time in the year that you must drink most of your cup (rov kos) of kiddush wine. (For kiddush on Shabbat and Jewish festivals, you need drink only 2 fl. oz., or 59 ml).  So if you have a cup larger than 4 fl. oz. (119 ml), you may have to drink a lot of wine--more than half of each cup for four cups! 

You do not need to close the wine bottle or cover the other wine cups while the first of several people says kiddush, whether on Shabbat or Jewish festivals.

You do not need to close the wine bottle or cover the other wine cups while the first of several people says kiddush, whether on Shabbat or Jewish festivals.

1 Revi'it = Usually 3.3 fl. oz. (99 ml); but 4 fl. oz. (119 ml) for:

• Any food requiring bracha achrona.
• The four cups of wine at the seder.
• Kiddush for Shabbat and Jewish festival nights.

 
1 Log = Volume of 6 eggs = 4 Revi'ot (a revi'it is 1/4 of a log)  
1 Kab = 4 Login  
1 Se'ah = 6 Kabin
 
40 Se'ah = Volume equivalent to 3 cubes, 24 ½” (61 cm) on each side; minimum requirement for mikva = about 192 gallons/750 liters  

1 fl. oz. = 1.77 cu. inch (about the size of a golf ball)

If a non-Jewish business makes a mistake in your favor, it is considered a saintly trait to correct the mistake. It is especially a kiddush HaShem to return the money to them if they know that you are Jewish.