Try to avoid what pro carpenters call a "growing pattern syndrome." This can occur when you are cutting a number of studs or other pieces to length, then always use the most recently cut piece to mark the next piece. The catch is that after two or three generations of cuts, the length can begin to grow longer. If, for example, each stud is off by 1/16 in., after you cut four studs, you will be off 1/4 in. For accuracy, it is better to use one master pattern and use it for every cut.
You can improve the visibility inside your workshop just by painting the walls and floors white. If your workshop is in the basement paint the sides of the window wells white too.