By enhancing armor sets with materials and resources dropped from monsters, you can acquire Perk Tokens. Spend these items to unlock Perks at one of the Anvils unearthed from the sands.

After unlocking a Perk, you can continue funneling tokens into it if the passive has multiple tiers, increasing its effectiveness. Naturally, that would also put you in a position to miss out on unlocking the base tiers for other Perks, so you’ll have to weigh your decision.