So you need tips for position battling for an outside or inside centre from an outside centre
To Impress the coach you must have really good hands or handling skills meaning NO KNOCK ON. Just catch everything.
You also have to be vocally loud when calling out set plays and Defensive patterns to the rest of the backs, a coach wants to see communication amongst the backs.
You must be great at the Sliding Defense or the attacking defense or umbrella defense or whicever defensive pattern because you have to cover a lot of space so slide your feet and stay in front of your man.
Shout it Out, Call the guy you are covering so you dont confuse your teamates and dont have switch move done right in your face.
The most important tip is try to stay on your feet after you break the gain line or break a few tackles, when you know you need support.....slow down,stay on your feet, wait for support and dont pop the ball in a crazy manner unless you know it will be catchable. Wait for the loose forwards than go down, set the ball and form a ruck and a quick ball.
Dont put all you hard work to waste by poping the ball to anybody, that'll be your ticket off the field. ( trust me)