I like to wrap the cake in a double layer of greaseproof paper and then in double foil.
Secure it all with an elastic band, then keep it in an airtight container till needed.
For those who like a well-brandied cake, a little 'feeding' of the cake at odd intervals (say, weekly) before Christmas will add an extra dimension to it. This is done by making small holes in the top and bottom of the cake with a darning needle, then spooning over teaspoonfuls of brandy to soak in through the holes and permeate the cake.
The traditional coat of almond icing (marzipan) should be put on the cake a week before you want to ice it, to allow its oiliness to dry out. Cover the marzipan surface with a clean tea cloth and store out of the tin or container. Icing is best left to the last few days – in my case often until Christmas Eve.