Like the other Viruses, "Crush Card" goes hand in hand with milling cards. However, due to this card's errata, you will have to be quick if you plan on destroying their Monsters without "The Fang of Critias".
After "Light and Darkness Dragon" has lowered its ATK to less than 1000 with its own effect, Tribute it to activate this card.
"Dark Mimic LV1" and "Dark Mimic LV3" are a pair of monsters that can be easily used in any Deck, for their own merits and for serving to activate this card.
"Apprentice Magician" and the accompanying DARK Spellcaster-Type monsters it can Summons can be used to activate this card.
"Black Garden" can supply an almost endless amount of ammunition to play this card. However, "Black Garden" will halve the opponent's monsters' ATKs, limiting the amount of monsters this card can destroy.
This card pairs well with "Dimensional Fissure" and "Soul Absorption". This card destroys every strong monster in the opponent's hand and on the field, "Dimensional Fissure" banishes them, and "Soul Absorption" gives its controller 500 Life Points for each monster banished.
If there are no DARK monster with 1000 or less ATK, but control monsters such as "Vorse Raider" or "Ryu-Kishin Powered" with 2000 or less ATK, use "Shrink" to halve that monster's ATK, so it can be Tributed for this card's cost.
Use a card like "Old Vindictive Magician" to destroy an opponents monster with less than 1500 ATK, then Tribute it to activate this card. Not only will it destroy one more of your opponents monsters, it will also get rid of a monster with low ATK points on your field.
Be very wary of using this card against Zombie-type decks, as they will most likely choose cards like "Despair from the Dark" and other Zombie monsters with similar revival tactics, to pretty much make this card's effect backfire.
Tribute a "Sangan" you control to not only destroy any monsters your opponent controls with 1500 or more ATK, but you can then search for a monster with 1500 or less ATK.