I find it very helpful to review the results for the last drawing session before I start the next one and critique that work. If I am doing portrait work, I move the layer over top of the reference so it is easy to see what's wrong. Most of the time, my portrait mistakes are from not paying attention to the underlying forms, so spending more time doing the full Loomis construction (and then overlaying that to check before moving on) is worthwhile for me.
I think you've made good progress with copying accuracy. What I'm seeing is that your facial features tend to be a bit smaller than your reference - most frequently the eyes. I draw my eyes too big, so I can relate to the struggle.