rendering help

[fluid zenith]

I really want to make
This much better because honestly it looks so flat

[deft onyx]

Oh oh pull up some references of other artists! :D

Here's some I personally like :D
You can see they all focus on the volume of the head a lot! Using shading to make it three-dimensional.
The first one is doing simpler shading, done only in a few key areas.
The second one uses very colorful and soft shading :0 rendering everything in detail.
The third again, uses a hard brush but has literally perfect placing of the shadows. You can see they're not afraid to cover large areas with shading to give the character proper form :0
And lastly the artists didn't use any shading in this piece, but made it feel so 3D by using the geometry of the face and highlighting it with the markings. They all follow the shapes of the face so perfectly :D

So it's totally up to you which route you wanna go for!

But to start I'd make a new layer, pick a color you'd like for the shading, set it to "multiply" or "overlay" (or whatever you see fit) and think about the shapes that make up this portrait.

So the face itself is an oval with a snout protruding from it. I'm that case if the light is coming from top left, you'd place a shadow on the right side as the muzzle casts it onto the face. And also on the right side of the face and snout in general since yk, one light can't hit all sides of a sphere at once