Alright so my good friend _Shadou_ had asked me a question of how to upgrade your trial deck so let's start!
So just to pick a random example I'll look at the Trial Deck for Dragheart, Luard. So with that build one thing to note is that the deck had the focus of it be Luard obviously so the best way to upgrade your trial deck is to figure it how you want to use Luard and from that change the units to fit your strategy. For example you have a normal perfect Guard in the deck (going by memory here 'XD) so one thing you could do to get around the counter-blast heavy nature of the deck you would replace the normal ones with Karma Collector or if you'd rather give Ritual more of a focus you add in the null with Ritual.
To sum up what I'm saying the best way to up grade your trial deck is to figure out what strategy you want to use to win against your opponent and when you make that decision add the units that you feel would be best to enforce that image you have for victory. I'll end it there for now but if I left anything out please feel free to comment your own ideas that you may have for _Shadou_ I'm sure she'd appreciate it. With that said let's all continue to live in this golden age together