Work in subassemblies. You need to be able to get into an area to paint it and the overhangs on a completed model make it difficult. Paint and apply guns, boats, and other details later.
Another approach to painting a ship is to paint the decks first (wood, steel it really doesn't matter - the process is the same).
Then go back and spray the hull & superstructure while you hold the ship tipped 45 to 60 degrees awat from you. Spray from the bottom up. Let the deck edges mask the deck paint leaving about the bottom quarter or third of the bulkheads unpainted.
Then when that is dry go back and hand paint the unpainted bottom of the bulkheads.
Then there is Mike Ashey's technique that he presented in the Kalmbach book on the Basics of Ship modeling. Paint the deck. Then cover the deck with masking tape snippets which leave the bulkheads and deck fittings exposed -- then spray.
I tend to prefer something which is a combo of both these practices on my ships. I do the decks then the coarse spray of the upper bulkheads -- then mask the deck and deck fittings and spray the lower bulkheads. I work in sections, fore, foreward superstructure, aft supestructure, port & starboard.
You need to try several methods and see what works best for you.