The Bite-Sized series of articles is meant to take the most powerful cards in Dominion and give a short explanation of what makes them powerful.
Teacher’s effect is extremely powerful because it offers the effect of a village, draw, and +Buy, all in the same card – you can almost always have some pretty great turns because of Teacher if you have enough time to set it up. You’ll want at least two spammable cards for Teacher to be at its best, and of course one of them can be terminal if you’re OK putting your +Action token on it.
Disciple is an excellent card as well, and it has a synergy with Teacher: Disciple likes to double action cards and gain more copies of cards if they are enhanced by Teacher’s tokens. iIf you’re going for Teacher, you’ll want to pick up additional Peasants so you can have one or two Disciples along with your Teacher.
Peasant’s main weakness is that it takes a while to get going. You can help things along with trashing and junking, but it’s unusual to get more than two of Teacher’s tokens out before the game is over. Soldier can help slow your opponent down, so when you’re not being contested with these Travellers, you’ll want to make sure to play two Soldiers each turn.