This info is about how I do my equipment, not what some manufacturers recommend or

All modifications and maintenance items discussed are the sole responsibility of the person doing said modification or maintenance.

I prefer wet.  Fill the fuel tank with fresh fuel and add some Stabil. Go for a short ride, 
this will mix the Stabil and the fuel, It will also allow the mixture to enter the carbs. 
The Stable will prevent gum and varnish, but does not last forever. Stable or similar products 
are available at your local car parts store.
dry. The fuel tank and carbs are drained of all fuel. This allows condensation to occur in 
the tank, which will cause rust. The carbs will also dry up, causing possible damage to the 
needle and seat, also the vacuum slide diaphragm.

A form of automatic battery charger will keep your battery healthy through the winter storage.
Depending on the conditions, some folks like to remove the battery and store it inside the home,
where temperatures are warmer.
A battery that is fully charged should not freeze, unless you live near the Arctic Circle.
Disconnecting the ground cable from the battery and attaching a automatic battery charger, may be
a safe way to maintain the battery and not effect the electrical system on the bike.

Proper inflation.

If the bike is stored inside, a light cover, similar to a bed sheet , will be good protection. A cover
that can breath will reduce the possibility of rust or corrosion.
Bikes stored outside will need special fitted covers.

If circumstances allow you access to the bike, starting the bike monthly will replenish any
evaporated Stable fuel mixture in the carbs. Oil will be circulated and parts will be lubricated.
Don't let the bike run to long....pipes will discolor and spark plugs may become dirty from
choke operation.

Remove the spark plugs and spray an engine protecting foam into the combustion chambers.
This product is available at boat supply stores. Install the plugs. The bike will smoke a
lot when you start it in the spring.

Parts on your bike that are likely to rust or corrode, apply a heavy coat of aerosol WD-40
or silicone spray. It is a mess to clean in the spring, but no rust.