Well, firstly, I apologize this did not get answered in time for your meeting. As much as we try to get to time sensitive asks quickly, it can be difficult to find them in our crowded inbox, so it can sometimes be weeks or months before we answer a question. I still think your question is important, however, so I’m going to offer you and everyone else a response.
I have never met with an editor, but I’ve done one-on-one critiques with creative writing professors numerous times. When meeting with any person that will be reviewing your work, you need to be confident, but you also have to be flexible.
Be confident. When you hand over your work, don’t panic! It’s instinct to panic as they begin reading, because you’re afraid they will judge what you have right away. In your panic, you’ll likely try to save yourself from their judgment by telling them, “It’s just a first draft,” or “I really wasn’t sure about that beginning,” or “I know there’s a lot of grammar errors.” Be confident that you are handing over work that is worthy of being read. It will not be perfect. Reading is subjective, so while one person finds it perfect, another will disagree. So let go of the idea of perfection. Moreover, your editor will be looking for problems, so don’t be thrown off or surprised when they find them. Be confident that you’ve got a great start, and get ready to make it better.
Be flexible. While you shouldn’t let a hard critique deflate you, do not respond by making excuses or insisting that you know it’s a problem. If the editor says, “This scene needs fleshing out,” don’t jump in and say, “Yeah, I know. I wasn’t sure what to do so I just left it that way,” or “I thought it might be boring if I added more.” or “I really envisioned this a short scene.” Making excuses or insisting that it stays the way it is can turn off someone critiquing your work. They are likely in a tough spot too, wondering how you’ll respond to negative feedback. Show them that you’re a great listener and that you appreciate their input.
During a critique, just listen. Take notes, nod, and answer questions if you are asked. If you have questions of your own, by all means, ask! If you need something clarified or you’d like them to elaborate, that’s certainly okay. It could also be that they didn’t touch on an area you were concerned about, so ask if they feel that particular section could use some work too.
After the critique, review all their suggestions. You don’t have to make a change just because an editor says so, especially if the suggestion will drastically change your plot, but consider their expertise and realize that the suggestions are there to help you. Once you’ve considered everything, make your decisions and do some editing/rewriting.
Listen. Consider. Decide. That’s really all there is to it.