What actions reward experience?

Solution 1:

XP is awarded for:

• Killing Opponents (+10)
• Headshotting Opponents (+5)
• Assisting Kills (+5, more if critical assist)
• Neutralizing Resource Point (depends on type, +5/+10/+15 IIRC)
• Capturing Resource Point (depends on type, +10/+15/+20 IIRC)
• Healing (+10 every x amount of health, +15 for healing multiple players)
• Hypospraying (+5)
• Damaging buildings (+10 every x amount of damage)
• Repairing buildings (+10 every x amount of repair)

Bonus on XP:

• Being in a squad
• Following commander orders

XP loss:

• Suiciding (-10)

I don't recall any other action giving XP.

Source: Me