Fitting out starts in the autumn when laying up and if this is done properly the fitting out can be done quicker and with less trouble (e.g. no seized up seacocks etc.)

In Autumn

Flush out water tanks and drain.
Run engine and flush through with fresh water, finally running through some anti-freeze or cutting oil.
Change engine oil, do not allow old oil to remain in engine during the winter.
Remove water pump impeller and store in a jar of water.
Slacken alternator belt.
Spray engine with a water repellent.
Strip seacocks and leave in a dis-assembled state during the winter.
Wipe down every surface inside the boat with a solution of slightly soapy water and a pine disinfectant.
Any ropes or cordage that can be taken home should be thoroughly washed to remove any salt, this also applies to sails and blocks.
Electronics should all be taken home, wiped down with a damp cloth, thoroughly dried and stored in dry conditions.
Batteries. Unless you have a solar panel, it is wise to check battery voltage occasionally during the winter and if this drops below 125 volts I would suggest you charge them.

In the Spring.

Again flush out your water tanks, add a tank cleaning solution, flush out again and finally refill.
Grease and refit seacocks.
Refit water pump impeller, but firstly examine the root of each blade (both sides) for any cracks and if found replace impeller. Also smear both sides of each blade with Vaseline and finally when fitting the impeller back into the pump, bend each impeller blade away from the direction of rotation of the pump shaft.
Re-tighten alternator belt and if possible run engine on fresh water before launching.
Electronics should all be re-connected and left switched on for thirty minutes.
After launching you might like to check your compass for deviation - remember that it has been facing in the dame direction for at least five months.
For the rest of the boat refer to "Things to check when buying a boat" as it reminds you of all the things that could possibly cause you trouble during the season.