Giving useful comments.
WHAT TO ESTABLISH FIRST
What kind of review they want.
WHAT KINDS EXIST
Is the argument right Is the structure right Is it clear Is it free of errors
WHY ASK
Correcting commas on a draft that needs restructuring wastes both parties' time.
WHAT TO COMMENT ON FIRST
Purpose and structure.
WHAT TO ASK
Whether it achieves what it is for.
WHAT TO COMMENT ON AFTER
Clarity, then correctness.
WHAT TO AVOID
Rewriting in your own style Comments on preference presented as errors Comments with no suggestion
WHY THAT LAST POINT
Saying something is unclear without saying why does not help.
WHAT A USEFUL COMMENT LOOKS LIKE
Naming what confused you, and suggesting an alternative.
WHAT TO MARK CLEARLY
Which comments are required and which are optional.
WHY
Writers cannot tell, and they address everything.
WHAT TO DO ABOUT GOOD PARTS
Say so.
WHY
It tells the writer what to keep.
WHAT TO DO WITH SOMEONE INEXPERIENCED
Limit comments to the few that matter most.
WHY
Heavily marked drafts discourage more than they teach.
WHAT TO REMEMBER
It is their document.