The other big thing I have found to be helpful is to have very detailed instructions (to and from myself) as to what qualifies as partial credit. You haven't mentioned your area, so I don't know how much this applies to you. As a chemistry and physics instructor, my standard practice for long-response question was to ask students to show their steps from the the information in the question to the answer (i.e. show their work) Typical things I would assign credit for were:
- Identifying the proper variable for the proper piece of information
from the problem (and explicitly stating it)
- Explicitly stating the equation they were using
- Explicitly stating the transform of the equation to show how it was solved (or multiple equations were combined)
- Explicitly stating the answer, with appropriate units, and
As for how I would go through the stack, it was usually by page, section, or question, depending on which made the most sense. For me, by page was only if everything on the page was a simple right wrong check. By section or question was based on how test items relied on each other; if there was a section of questions based around a hypothetical lab and its results, I would grade each student's section, complete all of those sections, and then move onto the next part of the exam. For my typical long responses, I would grade one long response at a time.