XP is awarded only for securing treasure and defeating monsters.
Treasure earns experience when it’s either (1) in an easily-transportable medium, (2) secured at a moneychanger, (3) secured in a structure owned by the character.
Treasure earns XP at a 1 GP : 1 XP ratio unless the DM declares otherwise based on the DMG’s EXPERIENCE rules.
XP continues to accumulate after racial level cap, and should be tracked.1)
The division of treasure is purely up to the players. Assigning more treasure to a certain character to level them up more quickly is a valid strategy.2)
Characters are assigned class grades at the end of an adventure/expedition as per the rules on DMG 86.
DM Note: This is useful in case your table eventually adopts one or both of the UA rules which increase level caps. It also comes into play for items like the Book of Exalted Deeds.