I use the real technique complexion blender brush which is made specifically for blending moisturizer and bb cream and it gives it a beautiful all over coverage that is even and light. Once I started using this brush, I can tell how much better it looks then when applied it by hand
I'd recommend using a sponge! This bb cream doesn't have a strong coverage so applying it with your fingers will only make the coverage worst. Go for a beauty blender, or you can go for something cheaper, obviously.