The four attributes in Metroplexity are:
Increasing Your Attributes
Attributes are gained through XP. Combat gives XP that is distributed between the attributes according to how each attribute was used during the fight, while other encounters often give XP to a specific attribute.
You can see how close you are to the next attribute by checking your character sheet (the character link in the top bar).
With enough XP, that attribute increases, as shown:
|Stat||XP needed from last level||Total XP Needed|