The key card is present but its support is thin.
Prioritize useful support such as Resolute Reinforcements or Prideful Parent.
Develop token makers, then cast Heroic Reinforcements before attackers so both new Soldiers and the existing team receive the bonus. Use Battlesong Berserker to make the best attacker harder to block.
Your deck enables the plan but is losing the early turns.
Take a castable early creature or efficient answer before another expensive payoff.
A pump spell needs a board and safe attacks. Do not fill the deck with temporary bonuses at the expense of early creatures, or spend every token on an attack that still cannot end the game.
The support is missing
Favor independently useful creatures and interaction if the narrow support does not arrive.