From what I've heard. A lot of people, me included, are very enthusiastic at the start of the year, ie. now, so we'll do a lot of holiday homework and as a result, we'll be well ahead for the first couple of months of school. However, the crucial part is after this period, those who continue with this enthusiasm are generally the ones that do achieve high. That's not to say that there aren't exceptions, they may just be incredibly talented or lucky in this regard.
Personally, I think holiday homework may be a little overrated. In fact, I think the best thing to do during the holidays is solid revision of your past year. This way, you're fully prepared to tackle the year ahead. This leaves you with a very good foundation for the newer and more difficult or extended concepts that you'll probably learn this year.
