101:1 All work that may be performed on yom tov may only be done if required for that day. One may not prepare on the first day of yom tov for the second day – even on Rosh Hashana – and one my certainly not do so for a week day. However, if one needs to cook for that day, he is permitted to use a larger pot and to fill it up even though he doesn’t need that much for the same day. What’s left may be used that night or the following day. This is permitted when it comes to cooking in a pot, since the food tastes better when a lot of meat is cooked together, so long as one does not say that the surplus is intended for night or the next day. One should just cook. (If one did verbalize his intention, the food may still be used – Mishnah Brurah 503:6.) However, when it comes to other foods, one is not permitted to add anything that would make it take extra effort in preparation. 101:2 Even something that is not actual labor, such as to bring in water, or even wine for kiddush or havdala, may not be done on the first day of yom tov for the second day. Nor may one put candles in the candlesticks or otherwise prepare to light candles for the upcoming night unless he also needs to use them for light before nightfall, or in a shul for its honor.