Candle Lighting on Yom Tov
This is the approved revision of this page, as well as being the most recent.
- Even though there are different minhagim about the order of lighting candles on Friday night, on Erev Yom Tov the Minhag Yisrael is to say the Bracha of Lehadlik Ner before lighting the candles. 
- There is a Minhag of those who say Shehecheyanu before they light Yom Tov candles. However, many authorities hold that one shouldn't make a Shehecheyanu over the lighting at that time. Rather one should either say it after the lighting or wait until Kiddish to hear the bracha then. 
- If on Shabbat Yom Tov the woman made a mistake and forgot to mention Shabbat and Yom Tov in the bracha she can't go back and recite another bracha.
Candle Lighting on Succot
- It is a mitzva to light yom tov candles inside the succa in order to enjoy the candlelight while eating. However, if there is any chance of them constituting a fire hazard, one must place the candles inside the home and eat by electric light. 
- Some women have the custom to light yom tov candles before yom tov has started, similar to Shabbat candles. Other women light yom tov candles just before Kiddush. It is preferable to light before yom tov begins. 
- Machzik Bracha 263:4, Mishna Brurah 263:27, Kaf HaChaim 263:43, and Sh"t Yacheve Daat 3:34.
- Rav Yacov Emden in Sh”t Sheilat Yavetz 1:107 writes that there’s a Minhag to say Shehecheyanu before lighting Yom Tov candles. However he expresses his wonderment about the Minhag considering that it lacks any source or basis expect it’s noting in the Kitzur Shlah or Eliyah Rabba. Nonetheless, he concludes that his wife actually had such a Minhag and he didn’t stop her from continuing the Minhag. Rav Ovadyah Yosef in Sh”t Yachave Daat 3:34 writes that it’s an improper Minhag based on the Leket Yosher (1 pg 49(3); a student of the Trumat HaDeshen) who implies this from the Or Zaruh 2 Hilchot Ever Shabbat 11. So hold many poskim quoted in Yacheve Daat including Chesed LeAlafim, Yafeh Lev, Petach Dvir, and Bet Ovad. Source Sheet: http://docs.google.com/View?id=dg37c33t_82f8tkwcz8
- Leket Shichacha Vtaut p. 394 citing Shraga Hameir 2:6 because once the candles are lit there's no way to make another bracha (see Magen Avraham 263:11).
- Chazon Ovadia, page 207
- Chazon Ovadia, page 210