Don't answer amen if you finish a prayer or blessing within 2.5 seconds after the prayer leader (cantor) finishes the same prayer or blessing as you are saying. However, in these three cases, you may say amen, even if you finish exactly together with the leader:

• End of yishtabach;
• End of Hallel;
• Ma'ariv's shomer amo yisrael la'ad.

 

If you said a fore-blessing and ate a snack, but then decided to eat bread and a full meal:

• If your meal will not contain any foods that have the same after-blessing as your snack--
  • Say the snack's after-blessing, and then
  • Wash your hands and say ha'motzi.
• If your meal will contain foods with the same fore-blessing as your snack (even the same food as your snack)—
  • Do not say the snack's after-blessing.
  • Wash your hands and say ha'motzi.

Less than 1/48th missing is still considered a whole loaf. So if you only have two challot (or other loaves of bread) for Shabbat, you might be able to use one loaf twice, as follows:

• Wash your hands,
• Say ha'motzi,
• Cut off a piece that is less than 1/48th of the loaf, and
• Eat it.

REASON You may consider the remainder of that loaf as still being a full loaf and you may re-use it for your Shabbat morning meal.
NOTE If you have pieces of bread or other mezonot, you may:

• Cut off less than 1/48th of the loaf,
• Eat the additional pieces of bread to make a total of at least 1.9 fl. oz. (56ml), and then
• Re-use the same loaf for Shabbat morning.

If you take off your tefilin because you have to, such as to go to the bathroom, or if one or both of the tefilin fall or slide off your arm or head, say: 

• Both blessings again when you replace the head tefila (tefila shel rosh) on your head.
• Only the first blessing when replacing the arm tefila (tefila shel yad) on your arm.
• Each blessing in its correct place if you took off both.

Less than 1/48th missing is still considered a whole loaf. So if you only have two challot (or other loaves of bread) for a Jewish festival, you might be able to use one loaf twice:

• Wash your hands,
• Say ha'motzi,
• Cut off a piece that is less than 1/48th of the loaf, and
• Eat it.

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.

1. Place arm tefila box (bayit) on center of bicep of whichever arm you do not write with (knot on the arm tefila should touch the side of the box). If you are ambidextrous, put the tefila on your left arm.
2. Say the first blessing, “lehaniach tefilin.”
3. Tighten the strap.
4. Wrap the strap around your arm seven times between your cubit (inside of your arm, opposite the elbow) and your wrist.
   Note If you wrap more times, it is OK.
   Note You may wrap the tefilin strap over a wristwatch or put a watch on top of the tefilin strap.
   Note Tefilin straps should not overlap with each other and should not be wrapped on top of the ulna protuberance, but if they do--it is permitted.
5. Wrap the excess around the palm of your hand (tuck in the end to keep it tight and out of the way).

When traveling, the proper practice is to:

• Finish eating where you begin eating, or
• Intend, when saying the fore-blessing, to continue eating while traveling.

ExceptionsEven if you did not intend to continue eating along the way, you may say the after-blessing wherever you are if:

To do Pidyon Ha'Bein:

• Pidyon ha'bein is done at least 30 days after the boy was born.
• The boy's father gives six genuine American silver dollars to any cohen. If there is no father, consult a rabbi.
• The boy's father says the blessing al pidyon ha'bein and she'hecheyanu.

 

Although women and girls are generally exempt from time-dependent positive commandments (mitzvot), they may do some mitzvot for which they are not obligated and it is considered to be virtuous behavior for which they will get a reward. They may say the blessings before each mitzva.

1. These are voluntary mitzvot that women may do:

• Lulav

• Sukka

• Saying the full shema.

2. Women and girls MAY NOT  wear tefilin.

 

3. Women traditionally do not:

• Say tachanun. 

• Wear talit or tzitzit (talit katan).

• Study gemara.

• Say kiddush levana or birkat ha'chama.

But these are not forbidden.

 

The fore-blessing for ice cream cones depends on which part you prefer to eat:
After-blessing

• Borei nefashot if you eat at least 1.3 fl. oz. (39 ml, or 1/6 cup--including cone, if you eat the cone) within four minutes.
• No blessing if you eat less than 1.3 fl. oz. in four minutes.