What age are we talking about? When children are young…toddler to elementary school grades, we should assume that they can paint and provide them with ample opportunities to paint. We should not relay solely on art courses to nurture this talent but incorporate art across curriculum. For example, I was working with 5th and 6th graders in summer. After finishing our book for the reading, one of the projects was that students have to draw their favorite scene and color/paint it. So you can have plenty of activities incorporated with other learning areas that would provide the child with opportunities to practice their art skills.
If the child is taking art class during the school or after school, the art teacher should be able to recognize the skills child excels. While teaching them other skills the teacher should make sure they somehow provide the child with opportunities to master the skill that the child is most comfortable with. This can also be done at home when parents are working with their children, they should be able to recognize what sort of art skill child excels in and provide them with different opportunities to practice that skill.
I am not quite sure if children will be really interested in watching videos. If you plan on using a video, then watch it before hand, get the supplies and have them follow the steps as they watch the video. You can pause in b/w and work with them so they don’t feel overwhelmed. Also, use video only once a week, if used more, child can lose interest. Use small duration videos, if it is a long video, watch it in parts. 
Make art a fun experience for yourself and your child.