Can one cut nails and shave/tweeze on Sunday? Or should these be done before Shabbat to honor the holiday?
Halachically it is permitted, however there are people that are careful not to cut their nails and hair right after Shabbos, if they could have cut them beforehand, because it looks disrespectful to Shabbos, that we are grooming ourselves right after it leaves.
It is brought in Shulchan Aruch (O:CH 260-1), that it is a mitzva to cut one’s nail on Friday, and when one needs a haircut to do it on Friday so it will be in honor of Shabbos. This does not mean that one is not allowed to take a haircut at other times, with the exception of Thursday. We don’t take haircuts or cut our nails on Thursday, because they start to grow back two days after they are cut and it isn’t considered kavod for Shabbos that they should start growing back then.