Iterative Island Instructions a go-to thread all about what kind of islands you can find.
Glossy Ship Gallery a big image of almost all the ship combinations. A:BaE doesn't have all the fancy 80% sails and event ships yet, but maybe soon?
Starting Out: Pioneers and Vassals a step-by-step guide explaining exactly what you need to get through the early stages.
Guild Creation Codex A:BaE doesn't have guilds, but if they ever do, there is a pretty good chance this is what it will cost.
1500 Vassals a comprehensive guide that starts off where "Pioneers and Vassals" ends. How to get ships, and how to get all the way to player trading.
Chat FAQ's a small set of FAQs that I used to answer in chat every couple minutes.
There are many other decent guides in that forum, but sadly of late its been filled with spam and "idk what is happening" threads. If there is demand, I may fine tune some of my calculating spreadsheets and post links to them as well.