I'm in Northern Europe. The most common routine here is to remove all sails and the boom, lower the mast and store it in a mast shed or on the boat. Engine oil and filters are changed with the boat still in the water, as it's easier to pump the oil out if it's warm, and that means running the engine so you want cooling water.

Then haul out and place it on the hard. You'll typically also powerwash off all the growth. Many also scrape and sand off the antifoul and polish the bottom, ready for a new coat in the spring.

The engine seawater coolant loop is drained, flushed and filled with antifreeze (ethylene glycol and water in the past, more recently often the much less toxic propylene glycol or even a glycerine and water mix). Seacocks are typically left open, to avoid ice forming in cavities, cracking them.

Cushions and most things made of fabric are removed, to be stored warm and dry. Food and other things that could rot, grow mold or otherwise cause problems over winter, are removed.

Water tanks and lines, as well as the septic tank if any, are drained and dried, again to prevent ice from breaking anything.

Batteries are charged fully, then fully disconnected to avoid any tiny current leaks, unless "shore power" is connected over winter (for heaters, dehumidifiers and charging), or lifted out and stored indoors.

If you don't use a dehumidifier, you'll probably use magnesium or calcium chloride to draw moisture out of the air, and combine that with sealing the boat mostly air tight. Some just leave it as it is, with air free to circulate. Both methods seem to work well for some, and cause problems for some, so there's no single right answer...

Most will then build a "tent frame" to cover the boat, with aluminium pipes and clamps, and cover it with heavy tarps, which are then tied down to weights on the ground.

And then the boat is left there until spring. Usually somewhere from March to May here.