The line quality in the portrait has a looseness that reads as confident even if it wasn't, which is the weird trick of working fast. What I'm noticing is the proportion in the face holds together even with the sketchy approach, which means either you got lucky with your initial construction or you've drawn enough faces that the muscle memory is doing work you don't have to think about anymore.

The silhouette reads immediately, which is the hard part with portraits when you're working dark on dark. The values in the face hold up even at thumbnail scale. One thing that clicked for me with tribute pieces was stopping before I overworked the edges, yours has that restraint, especially around the hair where a softer transition keeps it from feeling traced. Nice work.