Identify your use: baked filling (needs structure), stirred sauce (needs smoothness), or spread (needs spoonable creaminess).
Choose the substitute by texture: strain yogurt or blend cottage cheese until smooth; use mascarpone for rich dessert fillings.
Measure by the listed ratio. If the substitute is looser (yogurt/tofu), drain/strain or blend longer so it holds in your dish.
Taste and adjust: add a small pinch of salt for tang balance, or a tiny squeeze of lemon if you need brightness.
Proceed with your recipe. For baking, press out extra moisture from any wetter substitute to prevent a watery center.