UNDERSTAND THE TECHNIQUE
Use more than the full width
The distinctive fan shape invites you to work with the whole head every time. Also try a single corner, a slightly rotated position and a short sideways stroke. This creates different silhouettes without changing brushes. The broad shape suits groups and broken marks better than a precisely controlled individual line. It is this irregular effect that makes it useful for grass, foliage and abstract textures.
Paint quantity changes the pattern
A heavily loaded, wet fan can release a solid area of colour. With less paint, individual fibre groups become more visible. Moisture can gather fibres together and create new gaps. Make a small test strip: one dab freshly loaded, one after removing some paint and one with an almost empty head. Compare opacity and edges as well as shape. These three states already give you a small range of effects for your painting.
Think of foliage in groups
A painted tree is not a uniform wallpaper of individual leaves. Lay in the large crown shapes and their light and dark areas first. Then use the fan for selected groups along the edges and in lighter areas. Leave gaps through which the background or darker layers can show. Alternate between the corner and the full width. If you repeat the same imprint everywhere, the eye notices the tool rather than the intended tree texture.
Use acrylic and oil purposefully
Fleury recommends this shape mainly for acrylic and oil painting. The film mentions only limited possibilities with watercolour, so the fan is not recommended here as a general watercolour brush. For an acrylic texture test, choose a dry surface to help the new mark stay distinct. It can mix with paint that is still wet. With oil, the application depends on your chosen layering technique. Clean according to the medium used: water alone is not enough for conventional oil paint.
Know when to stop
Texture attracts attention, so it needs quieter areas as a counterpart. Pause after a few groups and view the subject from a distance. Ask whether the form already reads clearly. Additional dabs do not necessarily improve it. Add a few more distinct accents at a focal point, while allowing other areas to stay looser. If needed, use a narrow brush for individual important blades or twigs rather than trying to make the fan behave like a precise point.
All sketches show shape and movement direction schematically. The actual paint mark also depends on paint, surface and moisture.