Adding custom fields other than title and content on pages

Hi. I’m developing a website for my wife’s business. We’ve settled on a design and I’ve developed an HTML version, but I am trying to move it across to wordpress so my wife and a couple of other employees can update and maintain the website content and structure themselves. It’s not a complex site – 20-30 odd pages, all static html, a teeny bit of jquery, and a couple of (slightly complex) menus.

This is my first stab at wordpress, I’ve sorted some templates for a couple of different types of pages, an header and footer, but I’d like to make it a bit more sensible for them to edit the content.
In the ‘edit page’ screen you have Title and content boxes to fill in. Our standard page has an image at the top, a title, a sub title, content, and maybe another DIV with the same (title, sub title and content). How to I structure a template such that when my wife logs in to update it she sees boxes for each of those content areas?
I also need even more detail for the home page (it has about 5 or 6 <DIV>’s each with a title and content.
i’ve tried googling it but with no success, apart from a number of ‘custom fields’ plugins which I’m not sure is what I’m looking for.