There are quite a number of ways to take him out from what I've noticed during the fight.
1. Use a InfinityJump Sticker and hope you can keep your timing to take him out in one straight shot
2. Though I'm not so sure about this, but I think that using the Fan or any Thing sticker that can put out the lights in the background may work in order to make The Big Boo appear again so you can continue attacking.
3. The way I used just because I was experimenting in the fight. Which is to stock up on the Spiny Helmet stickers and pretty much make the thing stab itself to death after doing as much damage as you possibly can within the first turn.(Before the candles go out.) --- 3DS friend code: 5456-0116-3596 Xbox Gamertag: RiotB1ade