I wanted to have numerous outlets, and have enough electrical service that I did not have to worry about overloading circuits. There was already some lighting, so I simply picked off that line and added additional lights to keep things bright and cozy. I ran a 240V line for the table saw and jointer with a dedicated breaker. For wall outlets, I ran 14-3 wire, and split all the plugs, so that I can run one machine on the upper plug, and another on the lower plug of any outlet.
Electricity. It’s a rare workshop today that doesn’t need electricity; most need multiple receptacles of high amperage (20 amperes or more). Are there plugs available or will you need to add new lines and circuits? If you need to add wiring, when laying it out keep in mind that there’s no such thing as too many outlets in a workshop. The fewer (as in, ideally, zero) extension cords the better; they’re safety hazards. A good minimum is to have receptacles set at no more than six-foot intervals around the perimeter of the room, and, if possible, flush-mounted floor plugs in the central area.
Let’s be clear about one thing: No workshop is perfect for everyone. If there were, I could simply give you a precise plan to follow with clear dimensions. Every person who comes to the hobby, avocation, or profession of woodworking has his own particular collection of tools and his own peculiar work style, skills, and desires for the kind of woodworking he wants to do that gives him a unique approach as to how he will lay out a shop: where the tools should go, where lumber and supplies are stored, and how much bench area he needs.