I'm still pondering character creation guidelines, restrictions, etc, but you can start planning out character concepts, roles, etc. Make sure you take a look through the S&S Player's Guide for the campaign traits.
Big picture, you character should encompass two things into his/her personality: a desire to be a pirate, and/or adventure on the high seas of Golarion; and a more 'shades of gray' outlook than your average heroes. I'd like to avoid any pure evil sociopaths, etc, and good characters are still welcome, though more in the Han Solo/Lando 'scoundrel' territory.
I'd like characters that fit the campaign theme (i.e., paladins and monks need not apply). The swashbuckler in the new Advanced Class Guide looks like a great fit for this type of campaign. It's not on the PRD yet, but should be soon. Lastly, don't sweat not having a completely role-balanced group (tank, healer, caster, dpr)... If you all end up playing warriors and rogues, I'll balance out the threats appropriately.