If tu want to get a professional look when tu do your make-up then tu need to make sure that tu are using the right set of tools!
It is not possible to blend in your eyeshadow if tu are not using the right sort of brush. Every look and product needs its own brush. If tu look at what the professionals use, they have a brush for everything! Some brushes are for blending while others are for precise moves.
tu don't need to have a thousand brushes, but tu should have a good selection in your make-up kit.
Large brush for powder and liquid cover-up: The name says it all. This large brush is used to cover the face with powder and distribute it evenly.
Blush brush: Also large but thinner, this brush is for blush. Use it to spread blush along your cheekbones. Don't mix this brush with other brushes.
Eyeshadow brush: This is the one you're going to use to apply the color. It is short and thick with más of an edge than other brushes.
Eyeshadow blending brush: This is a softer brush used to blend in colores along the lids. Blend por moving it in circles.
Also, tu will need different brushes for different colors. Don't, for example, mix a dark blue brush with a cream shadow brush!