Moving from a great big house to a teeny tiny house

[Gremlingirl]

We move fairly often as part of DH's job and we have been lucky enough to have a big spacious house, with an attic and cellar for storage, for the last three years. We now have to move to a much smaller house with nowhere to store the piles of stuff we have accumulated over the past few years.
Where to start? I know exactly what the layout of the new house is so should I make a list? Just start throwing stuff out randomly? Hide in a corner with gin and chocolate? Please help.

You know where you're going so that's a positive. Decide how to use each room and what's needed in each room. The get rid of the rest.

Pare down before you move, but don't stress if you can't do it all. That's why storage facilities were invented.