Whether you're re-creating tradition or starting a new tradition, seeing how a work has been staged in the past is an informative exercise. Images of past performances, first hand accounts, and recordings are excellent resources.
Composers sometimes provided precise directions in their scores. You may also find information about what the composer had in mind for staging from autobiographies, interviews, and correspondence. Some composers are better documented than others, so in one instance you may have a flood of resources, and in others just a trickle.
Sources