DEBOLINA ROY
For foundation to adhere properly, the surface should be well hydrated. If you do not moisturize your skin type, the foundation will cling to dry areas and slide off from oily areas.
Choosing a shade that doesn't match your undertone typically produces a greyish or like mask. Always swatch on your jaw line under natural lighting to avoid one of the most common foundation mistakes.
Applying too much product to the skin creates a thick cakey feel, drawing attention to the skin pores and wrinkles. It's better to build coverage slowly in thin, light layers, just where needed.
Streaking and uneven blending can occur if you use a dirty brush or a dry sponge. The correct tools can help you get the desired finish (i.e., dewy type of sponge).