a few things
-write down all the key points he makes for you, you wont be able to do everything at once but knowing what they are down the line will be helpful
-don't be discouraged if you are advised to try something and you're not shooting 25s, having to make changes all at once is not easy, use what works in the beginning and integrate the advice you are given over time
-don't try and change your shooting when you get there, let them work with what you got and see how it goes
-if you have a trouble target presentation or post make sure you ask about it, it might be a really easy fix after he sees what you are doing
and finally
not everything he will tell you will work 100% in the long run, but you will have to eventually learn this on your own