Invest in luck gear.

This will give you a higher chance to re-roll for higher XP orb drops.

It took me 5 Thrax tickets to level up from 105 to 106 with minimum luck gear.

Then I learned about increased luck, and from 107 to 108 it took me just over 2 Thrax Tickets. I made 77000+ XP and 80,000+ XP on my last 2 Thrax runs.