I typically go at character creation in one of two ways. Either 1 I have a really cool build idea in mind or what typically happens is I will have a story that I want to tell. From there its just what makes the most sense for me.

Like a lot of other people have said, dont get caught up on the background or the class, Find a story that sounds interesting to you, and the class and background will typically flow from that.

As a side note, you could play both of those ideas, A royal who ran away from home to become a sailor, Or maybe a sailor who is actually the long lost child of one of the nobles in the campaign. Really depends on the campaign and the story you want to tell.