If you only buy one book about designing and organizing your sewing workspace, THIS is the one you should get. Dream Sewing Spaces: Design and Organization for Spaces Large and Small, by Lynette Ranney Black, is the most thorough, authoratative guide I've come across. The author, who has a background in kitchen and bath design and remodeling AND sews herself (she's even written a book on serging home dec projects) walks you through absolutely everything you need to think about when you plan a new or improved sewing space. I do want to point out that I'm reviewing the second edition of this book, published in 2010, not the original 1996 edition.
She gives you a handy Inventory of Needs checklist, a form for recording your body measurements for ergonomic planning purposes, and a nice overview of how to do a scale floorplan so you can work out the most efficient layout for your space. Black explains how to set up efficient U-shape and L-shape work stations to maximize efficiency. She covers how to do a full lighting plan for your space, including options for ambient, task, and accent lighting, and explains how wall and surface color choices affect how much light is reflected from surfaces -- and that wall color actually tints the light that bounces off the wall, so that you won't be able to view colors with as much accuracy in a room with pistachio green or hot pink walls, for instance. Some of my favorite specific storage ideas from this book were creating 3" deep recessed shelves between drywall studs (on interior walls) for serger thread cones and incorporating pull-out "bread board" style landing areas to the right and left of your sewing station. I'll be incorporating both of those into my own studio redesign.
This book includes lots and lots of big, full-color photos of very different sewing rooms for inspiration, and includes a floor plan -- with dimensions -- for each one. In the back of the book, the author even addresses the specific needs of specialty sewers: quilters, professional dressmakers, and drapery workrooms. Whether you're blessed with a large room dedicated to your sewing or trying to make the best use of a corner or closet, this book will help you to use your space wisely and efficiently.