Wives should light two candles for Shabbat (and Jewish festivals), even though we say the blessing over “ner” (“candle” in the singular). Lighting any more candles than two is custom.
 

Inviting friends to your house for meals, even on Shabbat and Jewish festivals, is not hachnasat orchim--unless the friends do not have food or a place to sleep. But inviting friends for meals may qualify as other mitzvot.

You may use water from a pump-operated well on Shabbat (as on Jewish festivals), as long as the pump operation is not a psik reisha (inevitable and immediate consequence of using any water tap).

You may not bite your nails or have them cut on Shabbat (and Jewish festivals).  If you have a broken nail, you may ask a non-Jew to cut it off for you if it bothers you.

You may not wash or hang up wet laundry on Shabbat (or Jewish festivals).  The halachot for drying laundry depend on whether you use a clothesline or a dryer:

Shabbat: Laundry: Clothesline
You may take down laundry on Shabbat only if it was dry before sunset on Friday, and only if you don't:

• Transfer the laundry from one halachic domain to another (hotza'a), or
• Give the impression that the laundry had been washed on Shabbat (mar'it ayin).

If laundry on a clothesline is still wet at sunset on Friday, the laundry is muktza and you may not take it down or use it during Shabbat. This is different from the case of a dryer.
Reason On the clothesline, there is no certainty that the laundry will dry during Shabbat (it might rain, it might be cold or cloudy...), so the person cannot have in mind that it will dry during Shabbat.

Shabbat: Laundry: Dryer
Laundry in a dryer (even if it was wet at sunset) that was turned on before sunset on Friday (or Jewish festivals) is not muktza, even if you do not intend to wear it.  You may remove the dry laundry from the dryer on Shabbat as long as no light goes on.

You may pick up and move an electric heater on Shabbat (and Jewish festivals) if it is:

• Off, in order to use the space where it is.
• On, in order to use the space where it is OR if you need the heat elsewhere.

Before eating bread (at any time, not just on Shabbat or Jewish festivals), dip the bread in some salt.

Before eating bread (at any time, not just on Shabbat or Jewish festivals), the bread should be dipped in some salt. This makes it taste better and makes it like a sacrifice (which had salt added to it).

Women and girls may not apply any nail polish or makeup on Shabbat (and Jewish festivals), including mascara and lipstick. You may not even apply lip coatings such as ChapStick, even if just to prevent chapping.
Note Beware of “Shabbat makeup” that stays on longer than normal makeup but may not be applied on Shabbat.

On Saturday morning, cut the upper challa of the two challot.  (For Jewish festivals, cut the upper loaf at night and day.)

You may not have your hair cut and you may not shave on Shabbat (and Jewish festivals).
 

It is a custom to make round challa for Rosh Hashana and other Jewish festivals (except Passover!), unless Rosh Hashana falls on Shabbat.

You may add personal requests to the amida on weekdays (not Shabbat or Jewish festivals) in these prayers:

• For livelihood:
  • In the amida's 9^th paragraph (bareich aleinu), between mi'tuvecha and u'vareich shnateinu.
• For a general request:
  • In the amida's 16^th paragraph (shema koleinu), before ki ata shomei'a.
  • Even better, just before saying yihiyu l'ratzon.

 

A business whose sole or major owner is Jewish may not be operated on Shabbat (and Jewish festivals), even by non-Jewish employees.

It is an enhancement of our prayers to give charity at shacharit and mincha (except on Shabbat and Jewish festivals).