Lyra Colored Pencils

I know you're supposed to do when you mix red brown, yellow and blue crayons. But the colors are not really mix to form brown, but rather a strange mix where you can see parts of blue, yellow and red. Any recommendations or advice on what to do to get a better result? By the way I am using colored pencils Lyra, like Prismacolor pencils.

How many of each color do you use? Try pressing lightly and evenly with each color and see what happens. If you do not get brown first, then press slightly harder with each new color to get the result you want.

I think that Prismacolor is a better color to use use the most.