While just doing your make up and practicing until you get it right works for some, mostly teenage girls who have time on their side, getting professional help and then putting in mirror time makes a lot of sense.
As for Glow, yes it is entertaining, but like any “reality” show, it is far from reality. What I do appreciate about such shows are their liberal take on gender and such. The contestants are very diverse in the gender and orientation, and the more of that on TV the better for society. It is truly amazing what can be do with “makeup”, but they take it way beyond traditional makeup, which is a good thing.