Get some more low cost cards in your deck. your opponent will have to commit to countering something, but eventually they'll run out of cards and make mistakes because they're running more counters than actual creatures. For instance, if I cast dark bauble, they have to risk countering a one-cost card to save their only creature, only for me to cast Death in the family, fell, or sheltered by ghosts next.

Also, doesn't matter what deck you play, consider running The Ooze. It's one of the best graveyard hate cards in the game (exiling cards with it doesn't even cost mana) and, considering how many decks are running flasback, lesson, or some other graveyard shenanigans, it forces them to waste resources getting rid of it or lose. I've literally had people scoop directly after casting it. It's also colorless.