I don't like to rush these things so it's the middle of January before I start...
Step 1 - Christmas Cards:
Take down all the Christmas cards,
Go through the cards with our Christmas card list, recycling card backs and un-up-cycle-able ones,
Update the card list for next year,
Cut out up-cycle-able details (from this year's cards to make next year's cards) into a box, recycle/bin leftovers,
Put away Christmas card cut-outs' box into craft cupboard.
Step 2 - Choose a Tree/Area to undecorate:
Gather storage boxes, bubble wrap, step ladder and any non-Christmas decs to be put back into place, etcetera,
Set up a temporary pile spot for those decs etc. that are stored elsewhere from the rest,
Set to (stay on task) and gather everything into the boxes,
Put boxes away once filled into their designated spot (ensuring they're labelled),
Re-stage area as it usually is or as it will be for "winter,"
Dust, brush up as you go.
Step 3 - Repeat Step 2 for each tree/area
Enjoy the new season!