It has always been hard, and it will always be hard.
Even Richard Schmid still thinks drawing is hard, and he is a master.
Artists like to come up with ways to make drawing easier.
Some trace, some use grids, some project.
Me, I'm a freehand person. Always.
I refuse to use a projector because I am a snob, and I tried using a grid once because I saw it in a book and -- I kid you not-- I couldn't do the simple introductory exercise. Grids don't work for me. And I want to use and develop my drawing skillz.
I was trained to work from life and even when working from a reference photo, I carry that same workflow as if I was working from life.
Basically, just like everything in the universe, everything in a drawing is interconnected. My drawing teacher at Pratt said the first mark on the page determines the entire rest of the drawing, and I have found this to be true.
Everything in a drawing is relative to everything else. I measure placements in a very holistic way, meaning I am working with the entire picture as a whole. If something is wrong, fix it at the drawing stage. I have learned the hard way too many times that impatience to move on to painting knowing there is a problem with the drawing will just not work out well. Just fix the damn drawing.
Here is the drawing for Melissa with all my placement lines.
The drawing is the hardest part. Especially in a portrait. Millimeters count.
I made a little animated gif of the painting progression.