I use a gentle stroke when I colour with a felt pen so that I can pass over areas to make a shadow effect and also to obtain, by pressing more or less, a fluid colour.

I don' t cross over the lines so as not to stress too much or make the colour less precise, always colouring in the same direction without lifing the tip, tapping softly at the edges.

I fill in the empty spaces with a maked flow making the colour homogeneous.

If I happen to slip outside the boundary lines it' s not a big problem since I' m as careful as possible.