Ma'ariv on Shmini Atzeret and on Simchat Torah may be said from 1 1/4 hours before sunset. Kiddush must be said after dark.

Some say the pre-shema blessing in shacharit or ma'ariv with the leader. Best is to finish the blessing before the leader does and then reply amen when he finishes saying the blessing. 
 

Saying shir ha'ma'alot hinei bar'chu... before ma'ariv is a custom of some people, but it is not necessary.

If you are late to shacharit or ma'ariv minyan and start the shema before the prayer leader has finished saying “emet” at the end of the shema, do not say El melech ne'eman.
 

If you arrive late for any minyan (except ma'ariv) that is about to start the amida, try to finish saying your amida before the leader gets to kedusha, if you can.
If you know you will not be able to finish your amida in time to say kedusha with the minyan:

• Wait for the leader to start the repetition of the amida.
• Say the repetition of the amida word for word with the leader, including kedusha, until the end of the third blessing (ha'el ha'kadosh).
• Once you and he have both finished saying the third blessing, you may continue at your own pace regardless of whether you will finish before or after him.

If for any reason you have not yet finished saying your amida by the time the leader begins saying the reader's repetition, do not say amen or any other replies to the prayer leader's repetition. However, when he begins to say kedusha or kaddish:

• Pause in your own amida and listen without answering or saying anything.
• Once the leader has finished kedusha (that is, he has said baruch kevod adonai mi'mkomo) or kaddish (that is, he has said da'amiran be'alma v'imru amen), resume your private amida.

Outside of Eretz Yisrael, begin saying Tein tal u'matar l'vracha at ma'ariv of Dec. 4. In a secular leap year, begin saying it at ma'ariv of Dec. 5 (but there might be rare exceptions!).

Where: Amida 9^th paragraph
Error:  Said tein bracha or tein tal u'matar l'vracha in the incorrect season
Situation Did Not Finish Paragraph
What to Do You must return to beginning of paragraph (bareich aleinu).

Situation Already Finished that Paragraph
What to Do

• If you said tein bracha in the wrong season, you may add tein tal u'matar l'vracha  in shema koleinu, just before ki ata shomei'a...
• If you said tein tal u'matar l'vracha in the wrong season, you must return to the top of the paragraph.

Situation Already Finished Shema Koleinu
What to Do If you did not correct your mistake in shema koleinu, you must return to the beginning of bareich aleinu.

Situation Already Finished Amida (such as you are ready to take 3 steps backward when you realize your error.)
What to Do You must repeat the entire amida.
Note If you said tein tal u'matar l'vracha in the wrong season but you are in a place that needs rain, you do not need to correct yourself or repeat that blessing. 
 

Jewish festivals begin for men at sunset or when they say “bar'chu” in ma'ariv, whichever comes first.

If you forgot (or are not sure if you said) ya'aleh v'yavo of:

• If you forgot:  Repeat the amida of Rosh Chodesh shacharit or mincha.
• If you are not sure:  Repeat the amida with the condition that if you had said ya'aleh v'yavo the first time, the second time is a voluntary prayer (tefilat nedava).

As with the blessing ga'al yisrael in shacharit, the prayer leader should say out loud the blessing preceding the ma'ariv amida: ha'melech bi'chvodo. If you:

• Are up to where he is in the prayers, you may say the last blessing with him.
• Pray slowly and will not be able to join the minyan for saying the amida, you should start earlier than the minyan and catch up at ha'melech bi'chvodo.

 

The prayer leader should say out loud the blessing preceding the amida (ga'al yisrael for shacharit; ha'melech bi'chvodo for ma'ariv). If you:

• Are up to where he is in the prayers, say the last blessing with him (and don't say amen but do say amen in ma'ariv).
• Pray slowly and will not be able to join the minyan for saying the amida, you should start earlier than the minyan and catch up at ga'al yisrael.

 

Shabbat begins for women when they light the Shabbat candles or at sunset, whichever is earlier.

When Tish'a B'Av begins on Saturday night, the custom is as follows:

• Say baruch ha'mavdil when Shabbat ends. 
• Say the blessing on the candle after ma'ariv.
• Do not say the remainder of havdala at all. Instead:
  • Wait until Sunday night, after the fast is over, and then
  • Say only the blessing on the wine and the paragraph of ha'mavdil blessings.

Introduction to Missed Amida/Tashlumim
If you accidentally miss any amida, you may make up for it (tashlumin)--unless you intentionally missed it.

Amida: Errors: Missed Amida/Tashlumin: Regular Days
Missed Ma'ariv Amida
If you accidentally did not say the amida for ma'ariv:

• Say the normal shacharit amida the next morning with the other men in the minyan.
• Say ashrei.
• When the leader begins his repetition of the amida, say the amida along with him, word for word, including kedusha.
• After saying ha'el ha'kadosh, finish your amida at your own pace.
• If you are not with a minyan, say ashrei and then repeat the shacharit amida.

Missed Shacharit Amida
If you accidentally did not say the amida for shacharit:

• Say the normal mincha amida with the other men in the minyan.
• Say ashrei.

• When the leader begins his repetition of the amida, say the amida along with him, word for word, including kedusha.
• After saying ha'el ha'kadosh, finish your amida at your own pace.
• If you are not with a minyan, say ashrei and then say the mincha amida a second time.

Missed Mincha Amida
If you accidentally did not say the amida for mincha:

• Say the normal ma'ariv amida with the other men in the minyan.
• Say ashrei.
• Say the ma'ariv amida a second time. Skip modim.
• If you are not with a minyan, say ashrei a second time and repeat the ma'ariv amida.

Note At the next prayer service, say whatever is the correct amida for that later prayer service, even if it is not the same amida that you missed.
If you miss mincha on Friday, say the ma'ariv service for Shabbat and repeat that amida again.
Note Once the time for the next amida has passed, you may not make up the missed amida.
Example
If you missed mincha on Thursday, you may only say tashlumin for mincha as long as you may still say ma'ariv, which is daybreak of Friday morning.

Amida: Errors: Missed Amida/Tashlumin: Shabbat/Jewish Festivals
Even if you forgot to say a prayer service on Shabbat and Jewish festivals, say the next prayer service amida and repeat THAT amida to make up (tashlumin) for the one you missed--even if it is no longer Shabbat or the Jewish festival.
Exception
There is no tashlumin for musaf. However, you may say musaf until sunset, even if you already said mincha.
Note If the time for mincha has arrived (½ hour after halachic midday), you must say mincha before saying musaf (but if you could join a mincha minyan later, you may say musaf now).
Situation
You miss Shabbat mincha.
What to Do
Say ata chonantanu in ma'ariv, but only for the first time you say the amida, not the second time (which is tashlumin).
Situation
You forget to say ma'ariv on Saturday night.
What to Do
Say ata chonantanu on Sunday morning in the second amida (which is tashlumin).

If Doubt about Whether You Said Amida
If you are not certain whether you said an amida:

• On a weekday, assume that you did not say the amida and say it anyway.  Intend that:
  • If you forgot the previous amida, this makes up for it, and
  • If you did say the previous amida, the second one is a nedava (free-will “offering”).
• On Shabbat and Jewish festivals, do not say the amida twice as tashlumin.

            Reason You may not say a voluntary prayer service (nedava) on these days.
Men who intentionally delayed saying shacharit past the fourth halachic hour of the day still say that amida until midday but if they did not say it by midday, they may not say tashlumin. See Minyan: Keeping Pace: Shacharit Minyan.

Each son age 6 and above is required to say kaddish for his dead parent at least once a day.