ok, so, here’s the deal with ruler guides … there’s probably handy stuff you don’t know yet …
let’s start with the basics. you click-drag a guide from a ruler (if your rulers aren’t showing, hit cmnd-r). if you want a horizontal guide, drag from the top ruler. if you want a vertical guide, drag from the left ruler. BUT if you accidentally drag from the wrong ruler, just hold your option key before you let that button go and your guide will change orientation. cool.
if you want your guide to only traverse the page, you drop it on the page. if you want it to extend across a complete spread or across the pasteboard, drop it on the pasteboard. simple.
you can also drag a horizontal and vertical guide at the same time — hold your cmnd key and click-drag from your origin (these guides always traverse the spread/pasteboard) :
to select a guide, just click on it. to select a bunch of guides, click-drag over them. to lock your guides so they can’t be selected (and moved or deleted) go view > grids & guides > lock guides. to lock individual guides (rather than the whole lot) just select and lock them the same as you would an object — object > lock — or cmnd-L.
and you can lock all the guides on a particular layer by double-clicking the layer in the layers panel and then checking the lock guides box in the layer options window that appears (notice you can show/hide guides on a particular layer here too) :
an active (selected) guide is the same colour as the active layer. so, if you’re having difficulty seeing a guide as you drag it because the guide is the same colour as the background, just change the colour of the layer or choose a different layer to drag the guide on to.
the colour of a placed (deselected) guide is determined by your ruler guides settings. find this under your layout menu. setting the colour here only affects the guides you create from here-on-in. already existing guides maintain their original colour. change an existing guide by selecting it and then choosing ruler guides (which you can also access with a right-click once a guide is selected). go crazy.
this is also the place to set the view threshold of a guide — that is, the magnification level below which the guide will no longer be visible (unfortunately this isn’t terribly accurate — eg. in CS6, guides with a view threshold of 100% don’t disappear until 55% — you just have to get over it). if you want the guide to be visible at every magnification level — set the view threshold to 5% (the minimum magnification in InDesign) :
to quickly hide or show all guides use cmnd-; (also see the difference when you just hit ‘w’ — making sure your text cursor isn’t active at the time, of course — this is called preview mode).
to delete all guides on a spread right-click (or cntrl-click) a ruler and choose that command from the dropdown. this can also be accessed through view > grids & guides (this does not affect locked guides) :
but you might prefer to do it entirely from the keyboard — select all non-locked guides with cmnd-opt-g and then just hit delete.
to delete all guides throughout an entire document you need a tiny little script which you’ll find all the way back in InDesign scripting : lesson 01
if you just love precision (and don’t we all) you can use your control panel to place and distribute guides exactly where you want them. this screen grab shows what the control panel might look like with four vertical guides selected :
and now for tricky guides …
if you double-click the top ruler you’ll get a vertical guide in that position (left ruler gives you a horizontal guide, of course) — this is a great way to get a bunch of guides on the page quickly, before dragging them into exact position.
but the tricky guides are the ones you get if you use this method with the option key selected. they are partially protected guides. you can’t select them with the cmnd-opt-g method and they won’t be deleted when you choose delete all guides on spread. but these guides can still be selected and moved with your mouse and they can be deleted once they are selected. tricky — and handy.
note that the default view threshold of the tricky guides is the same as the magnification level at which they were placed. to change it, simply select the guides and right-click to access the ruler guides window.
but wait, there’s more …
if you want to place a whole bunch of guides in a regular pattern you can use create guides under the layout menu. this not only lets you create the familiar looking columns but also the less common but still-quite-functional-really rows :
and there’s still even more …
automatically placing as many guides for as many objects as you want :
and we haven’t even started on guide preferences, snap to guides and smart guides — but you probably already know all about that stuff.