To make sure you account for any existing obstructions, it’s a good idea to make a measured drawing of your workshop area on graph paper, noting existing furniture, built-ins and large items on the plan as you go. For example, a common one-car garage workshop layout has built-in tool cabinets and shelves around the perimeter where they won’t impede parking, but you may also have to get clever about folding work tables and saw horses that you can set up as needed in the middle of the garage when you’re working on a project (and cars are parked outside).
Shops can range from functional spaces adorned with unpainted wallboard to beautifully finished, painted, and trimmed-out spaces. Ultimately, I think it depends on your budget and how important your surroundings are to your mindset as you’re working, or to your clients’ if they will be viewing your shop. If finishing your shop will improve the quality of the work that you will produce, thereby relaxing or inspiring you, or showcase for your clients the quality of the work of which you are capable, it may be a worthwhile investment. A more finished space may also allow for activities like parties or even a weekly poker game (as long as drinks stay off the tools).
Some of the most important decisions in laying out a shop involve the placement of basic machines, such as the table saw and jointer. Deciding where to put them depends in part on the scale of woodworking you do, which determines the clearance area around these machines if you need to handle long stock or large sheet goods. You’ll also want to consider work flow to avoid an excess amount of running around the shop to accomplish tasks, as well as how to power your machines without turning your shop into a snakepit of extension cords.