a brilliant little feature in InDesign is screen mode. it lets you quickly get a clean preview of a page — with all hidden characters, guides, grids, frame edges and the pasteboard hidden. in other words, you can go from this (normal screen mode) :

… to this (preview screen mode) :

… in an instant. there are also options for both bleed and slug screen modes.

you can access this from the view menu or, even easier, from the bottom of the tool panel (this grab is from CS2, other versions are similar) :

but by far the easiest way is with the simple keyboard shortcut ‘W’. just make sure you’re not editing text when you use it. you can have the text tool selected, no worries, just don’t have it active in a text frame.

but wait, there’s more…
the default background colour is light grey — a good, all-purpose colour — but you can change it to anything you like, in your preferences :