We've all heard the adage, "Show, don't tell". While many of us know how to use that in our writing (tips here), too few of us use it when giving feedback on someone else's content. And that's a pity.
Don't give vague feedback
Because feedback like "make the voice stronger", "it needs more punch", or -- my personal favorite -- "it needs to be more crispin" (still not sure what that means) doesn't really give the writer much to go on. Sure, you know what you mean, but that doesn't mean the writer necessarily does. Why? Because all those terms are relative.
Do give actionable feedback
But "make it more like this" accompanied by -- heaven forbid -- an actual example gives the writer a clear idea of what you want the final content to look like.