You need to use a very fine knife. The shavings will get everywhere so do the carving over a piece of scrap paper.
The tissue paper was good for wrapping the more delicate presents before wrapping them again in the brown paper. Again, I did the stamping over a large piece of scrap paper so that the ink didn't seep through to the table as the tissue paper is very thin.
I also found an old office stamp with letters so I could make the words 'Merry Christmas' for the little gift tags.
The stamps don't last very long since the erasers can be quite crumbly (I'm going to have to try some linoleum or rubber for a longer lasting stamp), but for a one-off project that's all you need really. They're also really versatile since you can make anything. Here's a little skull stamp I couldn't resist making.