Your best bet is probably to stop their set-up cards (Merchant/Komushroomo) before they go off, so things like Tribute to the Doomed, Divine Wrath or Ultimate Providence. I guess you could try Forbidden Graveyard, too, actually, though it doesn't have much utility outside of the Sylvan matchup and maybe Cyber Angels.
You don't have to be aggressive against them. You may wait until their's turn, so that they have to flip the monster by themselves. For doing so, it open many plays you can do because if you attack Sylvian, their effect will activate in the end of Damage step making not many cards or the cards you set this can activate. If they have to flip their monster, you can use your set card like Econ or etc
omega tip: use arcana character with skill spell specialist: add 5 different spell cards to your decks among them "tribute to the doomed" and "dark world lightning" and you will have good chance to start the game with one of these cards that counter sylv.
Anonymous
Malefic
