General Yom Tov Halachot
Preparation for Yom Tov 30 Days in Advance
- Many hold that thirty days before Sukkot one should start learning the halachot of Sukkot.  All agree that on the holiday itself one should learn the halachot of Sukkot. 
- This doesn't mean that a talmid chacham should stop this regular learning to learn halacha of the upcoming holiday, but rather it means that a question about hilchot pesach is given precedence to questions not about pesach.
Erev Yom Tov
- It is a mitzvah to take a hair cut on Erev Yom Tov or close to Yom Tov so that one's hair still looks nice. It is always permitted to cut one's hair on Erev Yom Tov even after midday except for Erev Pesach when one shouldn't cut one's hair after midday, chatzot.
- It's forbidden to make a festive meal on Erev Yom Tov which one wouldn't normally have during the week. 
- One shouldn't have a meal after the end of the ninth hour in the day just like on Erev Shabbat. When Shabbat falls out on Erev Yom Tov one should have Seudat Shelishit before the beginning of the tenth hour and if one didn't have it beforehand one can still have it but one should try to only eat a Kbeytzah of bread and not an elaborate meal to save an appetite for Yom Tov. See Not eating on Erev Shabbat.
Kavod and Oneg Yom Tov
Meals of Yom Tov
- One should have Lechem Mishneh (two loaves of bread) for the two meals of Yom Tov. See Lechem Mishneh. 
- Although the main obligation of aliya laregel during the times of the Beit Hamikdash was to bring korbanot, there is still a mitzvah nowadays to visit Yerushalayim and particularly the Kotel Hamaaravi. 
- In Gemara Pesachim 6a, Rabbanan hold that one should begin to learn Hilchot Pesach thirty days in advance of Pesach, whereas Rabban Shimon Ben Gamliel holds only 2 weeks. Rabbanan learn this idea from Moshe who taught the laws of Pesach Sheni thirty days in advance which was Pesach in Nissan. Shulchan Aruch 429:1 rules like the opinion of the Rabbanan. Mishna Brurah 429:1 writes that according to Rashi, Tosfot, and the Gra the same is true of other Yamim Tovim such as Sukkot, however, according to the Bet Yosef there is only a thirty day period in reference to Pesach.
- Gemara Megillah 32b states that one should learn the halachot of Sukkot on Sukkot. Mishna Brurah 429:1 quotes this as halacha.
- Chazon Ovadyah (Pesach pg 1) explains that the halacha in Gemara Pesachim 6a is relevant in regards to the laws established in Tosefta Sanhedrin 7:5 which state that a person should ask relevant questions and a relevant question has precedence over the irrelevant questions.
- Shulchan Aruch O.C. 531:1 writes that it is a mitzvah to take a hair cut on Erev Yom Tov. Piskei Teshuvot quotes the Pri Megadim who says that as long as one cuts one's hair within 30 days of Yom Tov that is considered as though one's hair is cut and isn't too long. He concludes that it all depends on the time and place as to when one's hair is still considered short.
- Mishna Brurah 531:1, Shulchan Aruch 468:1
- Rama 529:1, Mishna Brurah 249:8
- Rama 529:1, Halacha Brurah 249:12
- Mishna Brurah 249:8
- Rama 529:1, Mishna Brurah 529:9
- Sh"t Yechave Daat 1:25, Sh"t Kol Mevaser 2:10. see also Rabbi Yosef Kalinsky and Igrot Moshe YD 3:122