How do I determine a player's fighting prowess?

[Ungod]

I need to find a mentor or maybe I just want to create ranks in my mind.

[Muratus del Mur]

Being a good fighter is not just being able to win, but also learning how and when to lose.

High stats and balanced profile (won fights=lost fights) could be an indicator of this.

[Dracoloth]

You can look at a player's stats at their public profile url, the current format for which is: https://magicduel.com/member.php?p=playername