i dont store my riv, i no longer have it. but some things you should do prior to storing will be
clean everything(wash,polish,wax, full interior and engine detail)
remove the battery in a whole(some will say just disconnect it, i fell that it could leak battery acid so i remove it)
get stabilize fuel shit(its supose to help so ur fuel wont brake down)
or you can run the tank dry
get a car cover(no not a tarp from wal-mart)
lock her up and put cover on it and you will see her in the spring