Sup, snakker here, local forever beginner
Id say you might want to slow down when doing representational art studies like these portraits. It's hard theres no doubt, I find it helps to slow down mentally when starting out, I tend to haste and when that happens proportions go to hell. I find blocking in proportions geometrically first is super helpful to find where everything goes relative to each other, so I take a lot of time on that first, before constructing and then adding in lines to represent features, at least, when I manage the haste
cheers
