Day of Wedding
- A bride and groom shouldn't go outside alone the week after their wedding.
- Some have the practice for a bride and groom the week before their wedding not to go outside alone.
- Some have the practice for a bride and groom the day of their wedding not to go outside alone.
Fasting on Your Wedding Day
- Some have the custom for the bride and groom to fast on the day of their wedding. However, most sephardim don't have this custom.
- Moroccans generally have the practice that the chatan fasts but not the kallah. If there is a case of need even a chatan can eat.
- If the wedding is in the morning, some have the minhag is to fast until the chuppah and some fast the day before.
- Some hold that it is inappropriate for the bride and groom to hold hands before the chuppah. 
Practices for the Week Before
- There is a minhag that the chosson and kallah shouldn’t see each other for the week before the wedding.
- Halachic Checklist For Your Wedding Day by Rabbi Zvi Sobolofsky
- The Gemara (Brachot 54b) states that a bride and groom require a guard from dangerous demons. Rashi (s.v. chatan) explains that the reason that they are at risk is because the demon is jealous of them. The Rama E"H 64:1 codifies this as halacha that a bride and groom shouldn't go outside alone the week after their wedding. The Kitzur Shulchan Aruch 149:!2 agrees. The Bikkurei Yacov 669:13 offers another reason for this halacha. He says that a bride and groom are compared to a king and queen. Since a king and queen don't go outside alone, a bride and groom shouldn't go outside alone.
- Nitai Gavriel (Nesuin v. 1, p. 55, 4:5) writes that some chasidim and Ethiopian communities have the practice that a bride and groom don't go outside alone starting from the Shabbat before their wedding.
- Nitai Gavriel (v. 1, p. 55, 9:13) writes that some chasidim have the practice that a bride and groom don't go outside alone the day of their wedding based on a fear of the dangerous demons mentioned in Brachot 54b.
- Rama EH 61:1, Sh"t Maharam Mintz 109, Kitzur Shulchan Aruch 146:1, see TorahMusings for potential explanations of this practice, chabad.org
- The Chida (Birkei Yosef 470:2) writes that the Sephardic minhag is not to fast the day of the wedding. In fact, the Yafeh Lelev 573 adds that the Hari Besamim thinks that it is forbidden to fast since it is a day of celebration for the couple, comparable to a Yom Tov. However, the Ben Ish Chai (Shoftim no. 13) writes that in Baghdad chatanim had the minhag to fast on the day of the wedding. Rav Ovadia Yosef (Yabia Omer EH 3:9 and Yechave Daat 4:61) discourages the minhag.
- Magen Avot EH 61 p. 57
- Magen Avot EH 61 p. 57
- Rav Soloveitchik (quoted in M'peninei HaRav p. 272)
- Nitei Gavriel(Shidduch and Tenaim pg. 448.
- This minhag is also mentioned by Rav Yaakov Kamenetsky (Emes Liyaakov EH 65), Orchot Rabbenu part 4: pg. 248 says two weeks
- There is no actual source for this minhag in the Gemara or the Rishonim.
- Shu”t Maharshdam 31 quotes a minhag that chasan and kallah should avoid seeing each other from after the shiduchin, i.e. engagement, until the wedding. The Radak (Bireishis 24:64) writes that it is proper for a woman to be modest in the presence of her betrothed and not be seen by him until they are married.
- Rav Elyashiv in Mevakshey Torah 25:280, 27:48 says that the chasan and kallah shouldn’t see or speak to each other, even on the phone, during the week before the wedding. There are a couple of reasons that are given for the minhag.
- Some suggest that it is a harchaka, a way of distancing oneself from violating any prohibitions. See Rabbi Binyamin Forst’s sefer Laws of Niddah pages 458-459 for more information.