The same as so many others, I think doing as much before hand as possible is the best tip. Even mashed potatoes can be prepared ahead with butter and cream, microwaved the day of and fluffed up with no discernable off taste.
I made toffee every Christmas for years. Once in a great while the butter would separate out, I always wondered what causes that.
sarash has not yet posted.
The eternal question of gift-giving.