The only type of laws that may sometimes be overridden to help with shalom bayit (promoting peaceful family relations) or kibud av va'eim (honoring parents) is rabbinic law, not Torah law. A rabbi should be consulted in these cases.

Activities for socializing are not prohibited during the Three Weeks before Rosh Chodesh Av (but the activities might be prohibited for other reasons such as if they are dangerous).

All fasts start 72 minutes (normal time) before sunrise except for the Ninth of Av and Yom Kippur.  These include:

• 17th of Tamuz
• 10th of Tevet
• Tzom Gedalia
• Fast of Esther
• Fast by a groom and bride on their wedding day
• Fast for first-born males on the day before Passover. This includes first-born cohanim and Levites (levi'im).

If you are not likely to see the moon on any of the days from the 10th to the 14th of Av, you may say kiddush levana during the Nine Days.
 

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.

Begin saying L'David Adonai ori v'yish'i (Psalm 27) on the first day (at night) of Elul, not the first day of Rosh Chodesh Elul (the 30th of Av). The last day to say this Psalm is 22nd of Tishrei (Shmini Atzeret). This Psalm is recited twice daily, in shacharit after shir shel yom and in ma'ariv after alenu, including on Shabbat and Jewish festivals.

Before Tish'a b'Av we are in a type of mourning so the laws are similar to mourning for a parent. There are three stages:
The “Three Weeks”: The least severe stage starts three weeks preceding the Ninth of Av
The “Nine Days”:  The next-most severe stage begins on Rosh Chodesh Av.
“Week” of Tish'a b'Av:  The most severe mourning is during the “week” of Tish'a b'Av (beginning after Shabbat preceding Tish'a b'Av).

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.