There are currently a variety of ways to obtain experience points. Experience points are not reset during rounds.
Succesful attack: 10 XP
Succesful defense: 10 XP
Complete a research: 3 XP
Succesful spying: 1 XP
Succesful sabotage: 1 XP
Succesful sniper attack: 1 XP
Send aid: 10 XP
Medal #1: 10000 XP
Medal #2: 3000 XP
Medal #3: 1000 XP
Clan award: 4800 XP (split amongst members of clan)
Killing a player: 500 XP
Spend a turn on buildings: 1 XP
Resetting: -5000 XP
Missile hit: -5 XP
Defeat: -20 XP
Death: -250 XP
To allow newer players to catch up with older players, there will be a deduction in experience gained when a certain treshold is reached:
Once your experience is above 100.000, the experience gained is decreased by 10%
Once your experience is above 150.000, the experience gained is decreased by 20%
Once your experience is above 200.000, the experience gained is decreased by 30%