Listen before changing
Read a passage long enough to hear how the writer moves. Notice the sentence lengths, the way examples arrive and the words they use without strain. Those habits can be part of the voice. A single awkward line should not become a reason to smooth every paragraph into the same shape.
Then identify the actual difficulty. A sentence may have an unclear subject, an unnecessary qualification or a phrase that repeats a nearby point. Name the problem before rewriting. That helps keep an edit proportionate.
Preserve the thought
A clean sentence that changes the meaning is a poor edit. Keep factual statements and qualifications that belong to the argument. When a passage is uncertain because the source is uncertain, polishing away that uncertainty would make the writing less accurate.
Look for details that give the prose its character. An unexpected but relevant comparison, a deliberate short sentence or a mild disagreement can make the piece feel authored. Keep them when they help the reader understand how the writer sees the subject.
Read the changed passage as a whole
After editing a line, read the paragraph before and after it. The new sentence may be clear in isolation and still sound out of place. Adjust the join, or return to a smaller change.
The aim is writing the author can recognise and stand behind. A useful editorial discussion explains why a change was proposed and leaves genuine choices visible. It does not turn every preference into a rule. Sometimes the best decision is to keep an unusual sentence because it says exactly what the writer means.