A Simple Way to set up a bleed design in Photoshop

[Snake Blisken]

I always do this when I start on a full bleed design in Photoshop (I mean a design for print, obviously). I thought I share this one with you…

I create a new document using the exact dimensions
I add guides on all sides of the document (make sure Snap to Document Bounds is checked in the View menu)
I add the bleed area by enlarging the Canvas Size (Image > Canvas Size)

simple and smart and this will save you from calculating the document size from the start and by adding the width plus (bleed x 2) and dragging your guides in afterword.