If you wanna have the biggest ships, the largest houses and the best-looking of clothing then do this one tip: DON'T BUY SHIPS!
Its true. Ships are expensive and the gear is even more expensive. Of course, you'd have to board most of the ships you fight, but boarding ships reward more gold than sinking them. Plus the game gives you 4 ships free (1 raft, 3 skiffs). It'll take longer and possible make the game a tad bit more of a challenge, but it's worth it.
or you could buy ships. and still have enough money otherwise. on my privateer, i bought just about every ship i could. but, when i bought a new ship, i sold my old one. that gives you enough money. and all the ships the game gives you are, pretty much, trash. as for houses, you can't really afford them no matter what, until your lvl fifty. i don't mean to say you can't do whatever you want, it's completely up to you, just giving my input.