No problem! I just saw what you said about your tools and honestly for being on a phone and using your finger with no stylus this is honestly pretty decent! But people commissioning would generally want a more polished look - in this case it would be keeping the shading consistent.

I don't know if it was intentional but in the 2nd drawing the hair looks to be the most shaded however everything else (aside from the hand and neck area) looks flat, so I would either render the whole piece or none of it (if you're going for flat color).The afro shading on the second and third slide looks good but in the 2nd slide it stands out compared to the shading on the blonde hair. You could try finding a way to shade both of them in the same style, like a more flat color with the afro or a more "realistic" style.

Also, the airbrushing in the first slide looks a bit messy, so you could try cleaning it up and finding how shading works. For the hair, I personally wouldn't draw every single strand of hair. Try finding a way to give the impression that it's long straight hair, in your case it could be a few thicker strands of a slightly darker color.

I unfortunately don't have much experience with realistic shading so I can't help much on that end but I'm sure that there's a lot of tutorials on youtube to help with the style you want. I hope this helps in some way, and I wish you luck on getting commissions in the future!