This is a 3 hour study for a larger painting I have planned. The figure here is about 30" high and my intention was to keep it loose and free of any blending, letting the initial laid in strokes work as the final result. This approach gives a more linear or stroked on look and is always fun to do as it challenges your drawing skills to put down accurate brushwork from the beginning wihout going back into it.

Pencil drawing on rough canvas

Head blocked in

Robes blocked in

As a general rule- the heavier the texture of your canvas, the more your paint will pull away from each brush stroke, so you can lay on heavier paint. Alternately, a smoother canvas is ideal for slicker, softer edges and more blended passages.
I always sand down a too rough surface- with light sandpaper, just knocking off the drag you can feel with your fingertips. And, sometimes, I add texture to a too smooth canvas, either using oil white or, if it has an acrylic gesso to start with, you can add more gesso or even modeling paste, which is great for building up a really rough surface. I would caution not to use too heavy of modeling paste if the canvas is to be rolled or stretched later as it can crack. Only experience and the study of other artists works will guide you as to what works best. For portraits- a smooth surface is often desirable, but Fechin did some nice work on a very rough surface. For landscapes where the artist might want to drag across a rough surface, you can lay on a heavy undercoat of random brushed on texture (make sure to allow for extra drying time before painting over) . But I have seen some beautiful, highly finished landscapes done with very smooth canvas or gessoed panels. Its fun to experiment ahead of time and try everything! It keeps painting from getting boring and you can fine tune as you gain experience with what feels most comfortable and works best for the look you want.

Final head detail

At the Gate Study final 28x36" oil