Are you talking about basic organization, formatting the visual layout, or both? As far as I know, there's no way to create a brochure-style visual layout in Gateway's bbcode because there's no way to create columns. I can think of one way to do it if that, specifically, is what you want to achieve, but it involves creating images rather than simply formatting your text and probably isn't a great way to go if you have a lot of information.
But assuming you're talking the concepts of basic organization, I definitely have some tips (I actually did a whole
guide on organization a while back, but I'll boil it down here). The only separate information section the tab system features is one for rules. Everything else goes in one section. I find this is best handled by breaking up the section via the same kind of formatting you'd use in any other document -- larger, bolded section titles, bulleted lists, etc. Additionally, I love to use the hr tag (<hr></hr> except replace <> with []) which inserts a horizontal line like so:
With this, you can create the appearance of distinct sections.
Additionally, if you don't want all the information crowding your RP's homepage, you can create an extra OOC thread (or even several), put your setting info there, and add it to the game.