I did some red-lining to help you out. Drawing the head from a low angle like this is always tougher than drawing at a more even viewpoint. Hopefully this helps.
I'm not entirely sure how to help with some of the
specific changes you mentioned -- busted noses, how to make the eyes more "orcish," etc. But I can help with the overall face structure and a few details.
Now, onto the specific points you mentioned.
1.) The eye placement you have is actually fine. Eyes are roughly at the middle of the face, and you had them more or less right. Don't be too down on yourselfif they don't look perfect. A lot of the time we fool ourselves into believing something is wrong when we're not used to it.
As far as making them more "orcish," I don't have any specific pointers. That said, the character is
half orc so you can probably get away with leaving more human-like eyes. Much of the rest of his design says orcish. I probably would have pegged him as a full orc if I didn't know better.
As a side note, I'd make his right (our left) eyebrow longer and darker. At first glance, I thought it was another eye.
2.) The main issue with the nose is that it's flat, and I think you see that. This is arguably the hardest part to get right when you're drawing a face from a low angle like this. I struggled with it for a long time and I still wrestle with it often. What usually happens is the nose gets drawn out of perspective and it looks flat compared to the rest of the face. I do it all the time. You've done it here. The tip of the nose needs to stick out more, the top of the nose needs to scoot over more, and the slope needs to come out more. See my redline for an example.
I do not agree that this looks like a black caricature. I think it just looks like you have some things to fix. Like I said, this is probably the hardest thing about drawing the face like this.
Instead of worrying about making it gnarled or broken, I would worry first about getting it in the right place. It'll be easier to play with features like gnarling and misshapenness once you have the general anatomy down better.
3.) So when the tusks protrude from the jaw, this means a couple things.
First, the face is going to have one heck of an underbite. Most humans don't have a mouth that can accommodate protruding tusks. Our bottom teeth are typically
behind our top teeth. Orcs and tusky half-orcs, on the other hand, can't have dental structures like this because otherwise their tusks just go into their mouths. So you have to jut the entire jawbone forward more to accommodate. This means the chin should be more forward.
Second, tusks are bigger and thicker than the other teeth. That means the lower lip should look a little fuller to accommodate the teeth. You can see this in these photos of Spike from Buffy:
vampire Spike,
not-vampire Spike. Note how his mouth, especially the upper lip, looks more full when he's in vampire form. That's because all the extra volume from the prosthetic has to go somewhere.
A lot of the time if you move the jaw and chin forward enough, this takes care of itself, so you may not need to do anything specific. But if you find it still doesn't look right to you, try making the lower lip fuller to accommodate the bigger teeth.
4.) I would look at what another pencil artist has done to help with this. Either find some examples on Google or go to Youtube and find a tutorial. I say this because depending on your specific style and approach, there are a million different ways to pull this off. Someone going for a more realistic look would draw this differently from someone like me who draws in a comic book style.
One thing to remember, regardless of your style and of the race of the character: The more lines you put on the face, the older the character looks. It doesn't matter if the lines are wrinkles or scars, every extra line ages the character a little bit. So that's something to keep in mind when you're taking another pass at it. Think about how old your character is versus how old you want him to look.
If you try fixing it and it's
still not working, it's okay to scrap it and start over from scratch. You can use the same angle or do something different. I find a lot of the time I just need to
stop and start over to get something to look right. Sometimes I draw roughly the same thing, sometimes I do it different. But if you get frustrated, it's never a bad idea to just start over.
Something else that may help you is to draw over a photo. You mentioned that you used a reference. If you can draw digitally, put that photo into your drawing software, then draw the basic facial structure over the photo, kind of like what I did with your sketch. This is a good way to understand parts of human anatomy that you might struggle with.
Also, the mention above that the mouth is about halfway between the eyes and the jaw isn't really accurate. It's really more like 2/3 or so from the eye to the mouth, and then another 1/3 to the bottom of the face. Facial construction really is kind of a whole thing on its own, though.
Hope this helps, and feel free to @ me if you have any questions