To unlock your premium account, you need to purchase it.
If you go to the store, you'll see a tab for "Premium Account" and the day/price ratio for each option. The bigger amount of days you purchase, better the value you'll get.
Having a Premium Account will provide you with several in-game perks:
- Reduced respawn time in battle.
- Increase RP and Silver bonus after each match.
- Increase the maximum number of RP and Silver you can get daily.
- Provide Unique Medal and Aircraft trail.
- Exclusive color for account name and account.