Too many of my students fuss and fuss over a wonky line, or worse, stop a sketch altogether because a likeness is lost.
But I think there is great fun in diving in with a bold pen and feeling about for the features, one wonky line after the other.
Finishing something leads to something else because you take all that experience with you as learning, instead of setting that experience down in a pile of frustration you could never sort through when you needed it.
Also it seems to me that some bit of likeness always peeks out, if you look carefully. And it’s that bit of likeness you can build on next time.