Also note unlike TFT Attributes will not be able to increase. You can increase skill/spell bonuses with experience, but not attributes.
Below is a brief rewrite of experience for consideration:
Experience Points (XP)
For each foe you defeat, you get a number of XP equal to that foe’s highest attribute. If more than one person helped, the XP is split evenly among the players who participated.
Successfully casting spells or using skills are worth 2 XP each time it is done in pursuit of overcoming a challenge or challenger during an the adventure.
At the end of an adventure, the referee can grant a reward of between 100 to 300 XP to a player for good game play, creative problem solving, quick thinking or good sportsmanship. This amount is discretionary and solely the province of referee decision making.
Improving Skills and Spells you know
To increase your bonus in a skill or spell you already know requires 200 XP x the new bonus level. For example going from +1 to +2 in a skill requires 400 XP (200 x +2 bonus). The maximum skill/spell bonus possible is +6. You may not skip bonuses as each must be bought in order ( +2, then +3, then +4).
Learning New Skills
An Adventurer may learn a new skill for 500 XP, and it costs a Wizard 1000 XP to learn a new skill. A Wizard may learn one new spell for 500 xp, and it costs and Adventurer 1000 XP to learn a new spell. Note learning new skills or spells applies if your IQ allows it by having space to learn a new skill or spell.