Practice work

your best work so far IMO. Really really well done. Great attention to tones in the eyes

Only thing i think you need to pay special attention to is that his mouth looks like its kind of got a weird, puffy/kissy-face thing going on. Link to the ref image for comparison?

Also, if I can make a suggestion: At least for my personal tastes, I like to avoid things looking very photoshop-brushed (I'm only JUST starting to try and change this in my own work). I've never really used lots of brushes, but recently, i realized that my work feels much much much more natural and (imo) interesting just having created 2 basic brush mods that I consistently use to mimic a more natural, varied brush style, adding a bit of variance and noise. When painting on real canvas, you have the benefit of texture and variation automatically being caused by the canvas and light hitting it, so I wouldn't at all consider it "cheating" to take a canvas or cement/stone texture and very lightly overlay it onto your photoshop paintings. I do it, and I think it just adds a feeling of texture that helps pop things and takes paintings from wacom-attempts to ....well... *paintings*.

The other thing is that (and I learned this from Asa), if you want to aim for hyper-realism you should try adding saturated red and orange hues to the nose and cheeks. It really brings life to people (I'm finding recently).

These things I mentioned are things I really really need to work on myself.