My First Face Drawing

Good morning dear readers,  I've been trying to learn how to draw faces by watching YouTube videos.  I think I have a good start on getting it right, but please bear with me I'm still a beginner.  I've been watching the Dina Wakley video and others.  I love using the grid method this lets me get a handle on drawing the faces.  Not sure how to go about painting the faces without messing up.  Would love some pointers so please let me know.  Any tips would be greatly appreciated.  If you haven't taken the plunge her video is really easy to get started on drawing so check it out.