In general, the right side is given priority in our actions. This is considered to be proper behavior and not just good advice; however, it is a custom, not a halacha.

To buy fresh kosher fish in a non-kosher store:

• If the fish is whole and has scales, it is kosher and you may buy it as it is.
• If the fish has already been cut, skinned, and/or filleted and there are no non-kosher fish in the store, you may buy it as kosher.
• If you want to have the fish cut, skinned, and/or filleted and there are non-kosher fish in the store, have the counter-person wash off the cutting board and knife with soap and water before preparing the fish and you may buy the fish as kosher.
• If the fish has already been cut (and there are non-kosher fish in the store such that there might have been non-kosher fish oil on the knife or cutting board), just scrape off a tiny layer from the cut surface of the fish.

The Torah commands us to be kedoshim (holy, or set apart), requiring purity in what we eat, how we speak, what we wear, and how we behave. Tum'a is spiritual impurity generally resulting from transitions from life to death (even in a small measure; for instance—sleep or cutting nails). Tum'a inhibits or blocks us from achieving holiness.
Since we do not have a “red heifer” with which to make purifying water solutions, all people are considered to have some level of tum'a today.
Although there are three reasons to ritually wash hands--to add kedusha; to remove tum'a; and to remove dirt--tum'a normally has nothing to do with physical dirt. There are many types and levels of tum'a, with no exact progression. The following guideline is approximately in descending order from most impure to least:

Sources of the Different Levels of Tum'a

• Dead body (touching or being in same building with a dead body);
• Cemetery;
• Carcass of any dead animal not slaughtered by shechita;
• Women during and after menstruation or after childbirth (but before they immerse in a mikva);
• Sleep;
• Possibly a bathroom;
• Your hands' transferring tum'a to wet food;
• Your hands' transferring tum'a to bread;
• Food from under a bed on which someone slept;
• Intercourse or seminal emission;
• Having your beard, hair, or nails cut;
• Leather shoes;
• Touching body parts.

Depending on the level of tum'a, purifying may require:

• Washing your hands by the Three-Times Method.
• Washing your hands by the One-Time Method.
• Immersion in a mikva. OR
• Sprinkling with water that had been treated with ashes from a red heifer (which we do not have now).

You may leave the sukka due to extreme cold or heat, rain, or bees. You should not stay in a sukka if it is raining or very cold or will otherwise make people suffer.
If it is raining on the first night of Sukkot and the rain is sporadic, wait until midnight before saying kiddush indoors.
If it is raining on the first night of Sukkot and the forecast predicts rain all evening, you do not need to wait to see if the rain will stop before saying kiddush. Instead:

• Say kiddush in the sukka (without saying leisheiv ba'sukka), even in the rain.
• Wash hands and say ha'motzi.
• Eat at least 1.3 fl. oz. (39 ml, or 1/6 cup) of bread in the sukka.
• Go inside the house and finish your meal inside. 

Restrictions during the Nine Days before Tish'a b'Av are the same as for Three Weeks, plus:

• You may not eat meat or drink wine.
  Exceptions

  1. You may drink wine on Shabbat (but not on Rosh Chodesh Av or erev Shabbat.)
  2. You may drink wine for havdala (but ideally give the wine or grape juice to a child between ages 6 and 10).  
  3. You may eat meat or drink wine at a brit, siyum, or pidyon ha'ben.
• You may not wear freshly laundered clothes, or wear or buy new clothes.

• You may not wash yourself for pleasure.
  Note Showering or bathing to clean one's soiled body is permitted (except on Tish'a b'Av).  So you may bathe or shower during the Nine Days if you are dirty, sweaty, or smelly.
• You may not do any activities that involve luxury.
• You may not say she'hecheyanu except on Shabbat.
  Note Therefore you should not buy new fruits or new items that you will enjoy during the Nine Days.  But if you DO eat a new fruit or buy something new, you must say she'hecheyanu anyway.

Yom Kippur is the Day of Atonement. In ancient times, it was more festive than now and unmarried people of both genders would meet and try to find their future spouses.
Yom Kippur is a serious but also a happy day, since all Jews who repent (do teshuva) have their sins forgiven on that day.
Teshuva has four main parts:

• Charata  Regretting what we have done and feeling bad about it.
• Vidui  Recognizing and admitting that we have done something wrong.
•  Kabala  Resolving not to repeat that mistake.
• Azivat hachet  Being in the same situation as before but avoiding doing the sin.

The Torah tells us that there is an inherent property to Yom Kippur that causes spiritual purification and removes sins.
All Jews can become like angels on Yom Kippur.  In order to imitate angels (which are spiritual beings), we abstain from five activities that are associated with physical beings. We do not wash, anoint our bodies, eat or drink, have intimate relations, or wear leather shoes. To further imitate angels, when we say the shema, we say Baruch shem kevod malchuto l'olam va'ed out loud, as opposed to the rest of the year, when we say it quietly.
For more on fast days, see Fast Days.

Introduction to Fast Days
The purpose of Jewish fast days is to make us reflect on our behavior and improve it by:

• Eliminating negative actions and thoughts, and
• Taking more care in our observance of the commandments.

God told the Jewish people on many occasions that He did not want their pointless sacrifices or fast days but rather wanted the Jews to improve their behavior. If people fast but still have reprehensible behavior, the people have missed the point and purpose of bringing sacrifices and having fast days.
All fast days may be circumvented for health reasons. Consult a rabbi.
Fast days come in several varieties:

• Major fast days: Yom Kippur and the Ninth of Av (Tish'a B'Av). 
• Minor fast days: There are four minor fast days; see below.
• Fast for First-Born
• Individual Fasts

The Major Fasts
Yom Kippur and the Ninth of Av begin before sunset and are both slightly longer than 24 hours. Yom Kippur is a festive day while, on the Ninth of Av, Jews mourn for the destruction of both Jerusalem Temples (the first was destroyed by Babylonians; the second, by the Romans). On both fasts, it is forbidden to:

• Eat or drink.
• Wear leather shoes (but you may wear any other clothing made of leather).
• Bathe (or even to wash anything more than fingers; you may not use a deodorant--not even a spray type--since it is similar to washing).
• Have marital relations.
• Use cosmetics or body scents.

The Minor Fasts
The four minor fasts begin 72 minutes before local sunrise. They technically end at dark but functionally end after ma'ariv (and for the Fast of Esther, after hearing the megila). Unlike most times in the Jewish calendar, this 72 minutes is normal time and NOT based on the current length of the day (sha'a zmanit):

• Fast of Esther (Ta'anit Esther): Day preceding Purim (or sometimes earlier).
• Fast of Gedalia (Tzom Gedalia): Usually the day after Rosh Hashana.
• Tenth of Tevet (Asara b' Tevet):
• Seventeenth of Tamuz (Shiv'asar b'Tamuz): Beginning of the Three Weeks of semi-mourning beforeTish'a b'Av.

On all fast days, eating and drinking are forbidden. The Tenth of Tevet and the Seventeenth of Tamuz additionally have the same restrictions as the Nine Days. So you may wash or bathe on the Fast of Esther and on Tzom Gedalia but not on the Tenth of Tevet and the Seventeenth of Tamuz. (See Nine Days: Restrictions).
Note On a fast day that has been delayed for Shabbat, there may be leniencies for:

• The mohel, sandak, and father of a baby getting a brit mila to eat after mincha.
• Pregnant or nursing women (this leniency applies to eating throughout the day).

Fast for First Born
Fast for first-born males 13 years old and older, on the day before Passover. This includes first-born cohanim and Levites (levi'im). The fast begins 72 normal minutes before sunrise and ends with kiddush at the seder. However, the widespread custom is to attend a siyum on the day before the first seder so that the first-born men do not need to fast on that day.
 
Personal Fasts
Fast by a groom and bride on their wedding day is an example of personal fasts. This fast begins 72 normal minutes before sunrise and ends with drinking wine under the chuppa.

Whether a food made of the Five Grains qualifies as bread (ha'motzi) or mezonot (borei minei mezonot) depends on whether the food was intended to be eaten as a meal or as a snack, as follows:

• Bread for a meal: Say ha'motzi.
• Mezonot (but you will eat a full meal): Say ha'motzi.
• A snack (including bread as a snack): Say borei minei mezonot.
  Note Some foods may qualify as either ha'motzi or mezonot (such as pizza).
  Note Whether the bread/mezonot was made with fruit juice instead of water may not affect its blessing, since the blessing is determined by the food's intended use. “Mezonot” rolls on airline flights may still require the blessing of ha'motzi if you eat them as part of a meal.
  Note Bread that has been cut into small pieces and fried may be reduced in status from bread to mezonot.

In a non-bread food containing a mixture of grains, at least 20\% of the main ingredients must be from one of the Five Grains in order to require the fore-blessing (bracha rishona) of borei minei mezonot (after-blessing:al ha'michya).
If at least 20\% of a bread's flour is from one of the Five Grains, say a fore-blessing of ha'motzi (and birkat ha'mazon afterward if you ate at least 1.3 fl. oz. within four minutes).
Normally, the fore-blessing for bread (ha'motzi), or for other cooked or baked foods made from flour (borei minei mezonot), will override the remaining foods in a food mixture.
Say borei minei mezonot over:

• Cholent whose main ingredient is barley;
• Ice cream cone (ice cream + cone)—see “ice cream cone” for further details;
• Pie; and
• Cheesecake with any kind of crust.
  Note Cheesecakes are sold in bakeries and not in cheese stores, indicating that the mezonot part is more important than the cheese part as regards fore- and after-blessings.