A dry pastel sketch of the Île de la Cité in Paris. Notre Dame cathedral is on the same island. I began by lightly drawing the compostion using a warm colour such burnt sienna (a warm grey can be used). The choice of a warm grey paper enabled me to concentrate on highlights and shadows without having to cover every square inch of the paper. The highlights seem more luminous as well.
I filled in the sky getting lighter towards the bottom. It's not necessary to begin with the sky but I find that helps me to define the subject working area and to balance tones in relation to the sky. I try to place highlights quite early on rather than overlaying them on other colours in order to achieve the purest and most unsullied colour. In general , the highlights are where the purest colour is to be found. Working with the edge of a pastel stick, quite fine detail is possible. I use fingers for blending.
For trees I err on the side of warm greens in general.