Outside of Eretz Yisrael, Jewish festivals are observed for two days instead of one.

Say she'hecheyanu for:

• Acquisitions,
• Jewish festivals, and
• New fruits. 

To say hallel on Shabbat and Jewish festivals:

• You do not need to say full hallel immediately after shacharit.
• You may say musaf and/or hallel after mincha.
• Once it is time for mincha, you must say mincha before saying musaf or hallel (if you have not said musaf or hallel yet).

As on Shabbat, don't fast on Jewish festivals (except Yom Kippur!) past halachic midday.

• If you will not finish shacharit before halachic midday, you should eat or drink earlier in the day, even before you begin shacharit—water can be sufficient for this purpose.
• If you will finish shacharit, but not musaf, by halachic midday:
  • Finish shacharit,
  • Make kiddush,
  • Eat some mezonot, and then
  • Return to say musaf.

You should give charity daily (except Shabbat and Jewish festivals) at the time of prayer.

If you forgot to say ata chonantanu after Shabbat (or Jewish festivals), you do not need to repeat the amida. But, if you then ate food before saying havdala, you must repeat the amida including ata chonantanu.

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).