First, place at least 3rd in Castle Trodain under Standard Rules in the Dragon Quest Tour. Afterwards, purchase the unlocked "Highly-Strung" personality and the "Zealot" play style. This will give your Mii character a "Dominating" COM intelligence. Now, when you play a board, set yourself to Out to Lunch, and the COM will play for you. The COM will be able to place first in games the majority of the time, and the win will still count. This trick is especially useful for those who just want to unlock all the content for multiplayer as quickly as possible.