Trevor Gerzen's Blog

I don’t know why I never did this before, but I just realized I can create guides the way I like ‘em and save it as an action in Photoshop. I often like to start out with a horizontal and a vertical guide right smack in the center of the canvas.

Fired up an action, went to View > New Guide… > Horizontal: 50% then do it again for Vertical and you’re done. Obviously you could do the same thing if you wanted to break things up into 3rds or 4ths, but I don’t think it would be very efficient to do it for things like grid systems where you’re creating 16 or more. I would probably just reuse a file with the guides already created over and over.