the above helps, however there is no such thing as rust or corrosion proof.
wiping a wet bike off with a shop towel helps.
keeping the little "limber" holes clear helps to drain water out of the frame.
hanging bike up so moisture can flow to those cleared holes helps.
turning a fan on the hanging bike helps dry out the saddle faster.
also if real soggy, I lightly spritz the chain with wd-40 and wipe it off,lightly
with a paper towel - I know some will throw flame about the Wd-40 use.