I reckon Holdsworths errors stem down to a few things.
1. Trying to rush plays, due to over excitement.
2. Trying to be the hero in every play.
3. Not being aware of his fellow players around him.
He needs to just settle down, slow things down need be, and take the game play by play. Instead of thinking about how he's going to score a try, think about getting to the line. Instead of thinking about how can I chip to myself, think about the fact it's the first tackle.
In short he needs to play a smarter, more sensible football game.
I have no doubt he's capable of doing it, because against say the Storm, he showed flashes of individual brilliance.
If he's on here I have a simple message for him: Play as you would play in a team. Don't take it upon yourself to set up and score every point.
Take into account the above and I reckon his game will change dramatically.
Note that even in NSW Cup the above notes showed.