Simple, win a game in 2 vs. 2 online multiplayer.
All online achievements can be booster, check the achievement trading thread HERE for fellow boosters.
Setup that should be used for boosting:
- Player 1 (loser)
- Hero: Fiona
- Core Units: any assortment you want, you will be deleting them anyway
- Elite/Champion Units: Pick any 2 champion units. They take up more space and you can delete 4 spaces quickly.
- Artifact: Spider Cloak
Player 2 (winner)
- Hero: Anwen
- Core Units: Archers
- Elite: Druids and Unicorns
- Artifact: doesn't matter
The point of this setup is that Player 1 will only have 25 health and Player 2 will attack fast. Player 1 should delete as many units as possible in whatever columns Player 2 tells him/her. This makes it so Player 2 can attack quickly, and efficiently. This should maybe take 3 turns if you get lucky from the start.
After Player 2 wins, play the same game over and over until Player 2 reaches level 8 or so, then switch. This way Player 2 gets to 8 fast due to his/her streak of wins. Then switch and boost Player 1's level to 10. Player 2's level should raise from 8 to 10 helping Player 1, but if it doesn't just do some cleanup games.
Thread for online strategies with tips HERE