Layers and a stump
How you blend your coloured pencils together makes a huge difference to the final effect. I prefer softer blending, which is achieved with a blending stump. After each light layer, I very gently blend the coloured pencils with the stump. Don’t push too hard or the colour will stick, making it more difficult to softly blend. I repeat this process as often as I need. After many layers it produces a very soft and delicate look. There’s some trial and error, though. Sometimes when blending too softly, the colours already layered will pick up off the paper.