Graveyard decks are essentially a control based archetype so you need to play passively until you know what your opponent is playing then you can try to bait out their counter and punish them when the time is right. If your opponent plays a high elixir unit you can punished the opposite lane too. The bats, goblin gang and dart goblin all act as a spell bait card for log and zap, both of these spells can be used to counter your offensive graveyards or reset your defensive inferno tower. You have the barbarian barrel to act as a tank for the graveyard to and you can support your pushes with you cycle units to try and get extra chip damage. Only use the posion to support the graveyard if they play a card which can offer you a positive elixir trade such as any of the wizards, dart goblin, goblin gang archers or minions (basically any card over 3 elixir which your poison spell will take out or leave with a low amount of HP)
Mega Knight is a key defensive unit in your deck and in some matchups you won’t even need to play this card. He is exceptionally good against bait deck, bridge spam and three musketeers. He can take out support troops while the inferno tower takes down their tank.
Graveyard is your main win condition in this deck but because of the combo with mega knight the opponent won’t be expecting you to be playing both units. For the most optimal placement of this card check out my video to see where my pro guest plays this card. It is also good counter to a elixir collector if the opponent plays it behind their tower, you should place the graveyard so outside of the arena leaving just enough for it to cover the pump.
Early game you should cycle your units and see how your opponent responds, remember what counters they have for the graveyard and if they have posion or a few spells you can use your cycle units to bait out their spells. Only go in for a graveyard push if you have a good elixir lead or the opponent has played an elixir pump or placed a heavy tank behind their towers. If your against lava hound you will need to punish opposite lane as soon as they place their lava hound.
Later game you if you have the tower advantage you can cycle inferno towers and just play defensively until the match is over. sometimes the best offensive pushes can come from a counter push and your biggest counter push unit is the mega knight. Goodluck playing this deck everyone it’s great for either ladder or challenges!