The key card is present but its support is thin.
Prioritize useful support such as Llanowar Elves or Grow from the Ashes.
When possible, cast Tatyova before the turn's land drop, or follow her with Grow from the Ashes. Each land entry supplies a separate draw and life gain while advancing your mana.
Your deck enables the plan but is losing the early turns.
Take a castable early creature or efficient answer before another expensive payoff.
Do not keep a hand that only ramps and never affects the board. Save a land for Tatyova only when doing so does not delay the mana you need to cast or defend her.
The support is missing
Favor independently useful creatures and interaction if the narrow support does not arrive.