> When I send a story out for beta reading, I go through and fix all the major spelling and grammar mistakes first. I shouldn’t need to, but people get hung up on the spelling and don’t see the story.

One good rule of thumb: people will respond to the weakest part of your argument. So instead of making it as long as possible, and addressing several unrelated points in an attempt to preempt all objections, it's best to cut out everything but the core of your message. The question I always ask myself whenever commenting here is, "is my comment strong enough?". If it isn't, I delete my comment. If there are weak parts, I prune them. It's better to leave an incomplete but strong comment, than a comment which tries to be complete but has several weak pieces.