Identify whether your recipe tastes too sweet or too flat first (sip the base mixer, if possible).
Start with the listed ratio for your chosen substitute, then add it in the same point in the cocktail process (e.g., before ice or after mixing).
If it tastes too sweet, reduce the substitute and top with a splash of dry vermouth or a citrus peel squeeze; if too bitter/harsh, add a small amount of simple syrup.
For tea-based swaps, steep or rest 5 minutes (especially vodka + Earl Grey) so the bergamot transfers fully.
Taste again and fine-tune with orange zest (aroma) or a tiny pinch of sugar (sweetness) without over-diluting.