Mark up changes clearly.
Unclear or ambiguous changes make typesetting slow, and can introduce errors. Supplying electonic files for any large sections of new text makes corrections to artwork faster, reduces introduced errors and lessens proofreading time.  

Define the roles.
Changes should only be made by the person responsible for that section of the report.  
There can be a tendency for second/third page proofs to incorporate many more changes as ‘new’ eyes view the layouts.  This means the schedule/budget blows out as author’s corrections are added. Agreeing roles/responsibilities and identifying the decision-makers early in the process should avoid this.

Keep true decision-makers in the loop.

It is unwise to surprise the decision-makers with page proofs for the first time late in the schedule. Their time is valuable, but exposing them to the project as it progresses allows you to manage their expectations and incorporate feedback earlier.