In this entry in our What Sets the Pros Apart series, none other than Julien “ Cydonia ” Perrault is here to educate us on how to build a deck lineup to play in a Hearthstone tournament. Perhaps best known for his victory in the 2016 Hearthstone Championship Tour (HCT) Americas Spring Championship, Cydonia has remained active in the competitive Hearthstone scene, and often provides excellent advice for how to approach the game at the highest level on his Twitch stream .

I want to compete in a tournament. How do I decide which decks to play?

According to Cydonia, there are a few layers to work through. The first one is simply knowing if you can play all the best decks equally (or have the cards to make them). If not, you should play what you have and are best with. If you can choose to build any deck, though, Cydonia says, “If they can be countered and you expect a lot of people to bring the best decks, then counter them. If they can’t be countered, play them.” He goes on to add that if there is an asymmetrical balance to the metagame (where rock beats scissors, scissors beats paper, and paper beats rock, for example), you also have to predict what people will bring correctly.

How do I change my strategy based on the tournament’s rules?

Cydonia says the first thing to figure out (if applicable) is what class you will be banning. “Figure out which deck to ban, then tech the other decks according to the rest of the expected meta,” Cydonia explains. In many tournament environments, deck lists will be open, meaning you can see exactly what your opponent has brought—but they also can see what you have. “For open deck lists, established strategies are usually better, since you cannot count on your opponent not knowing how to play against your deck,” he says. “You also can’t omit key cards and hope your opponent will play around them.”

What is the most effective way to practice for a tournament?

There are two stages to tournament practice, Cydonia says: early on, you should play a wide range of decks to get comfortable with your options. As you get closer to the actual date of the competition, however, he recommends focusing on specific, tricky matches: “Test the matchups that are harder to pilot and not as prevalent on ladder,” he says.

In terms of his own practice and preparation regimen, Cydonia says, “I make sure I get enough games with all the decks to have a good feel for them, then try to practice all the difficult matchups. If there isn’t enough time to practice everything, I talk with other players to figure out a good plan and mulligan strategy for every matchup I expect to face.” He says there is no specific routine for actual events, since travel requirements and environments vary, but he makes sure to have eaten and always have lots of water to drink.

What should I do to review after a tournament?

A step that top players take, Cydonia encourages players to review their games once the tournament is over. “Record the games and watch them with other players to spot mistakes or alternative lines of play,” he says. “Evaluate the preparation that was done, and identify causes for wins and losses.” He notes that while what’s being played will change from one tournament to the next, “You’ve got to be good at correctly figuring out what was done well, what went wrong, and separating out what can be improved.”