Choosing the wrong blush
Everyone has their own blush preferences. However, if your blush doesn't look natural, it's time to change it. While powdered blush tends to last longer, creamy-based versions leave a more natural finish. But you also have to take into consideration other factors: skin type and season.
Oily skin types usually prefer blush powder to obtain a matte effect. This is okay during summer, but in the winter when cold weather can be very drying, the powder might make it worse. Those with dry skin are typically better off with a blush stick, but it's not the best summer option for hot and humid days, when it can make you shine like a disco ball...
Just try to find the most natural, compatible option for you, depending on the circumstances.