When I built my shop along with all the other excellent suggestions mentioned previously, I thought it important to have many outlets for hand power tools. I hate having extension cords to trip over. I installed outlets every 6 feet along the walls at a height that I don't have to bend over to plug the cords in.
My forge is at one end of the building, in the darkest corner. The treadle hammer is nearby but towards the center. I have a work bench on one side for some of the cold work. The band saw, welding table and welder are on wheels, so they can go where needed. I have some material storage overhead and some in a corner where it doesn't interfere with operations. There is open space near the double doors for layout and assembly. Some how I have to work a part time paint booth into this. Shop is 20' X 24'.
No matter what, you'll wish you'd done something different. Good luck.