Hmm, if you're going for tougher, I think first thing you might wanna do is, get rid of some of the 'aged' definition in his face. You'd especially wanna lighten up on the wrinkling below and around the eyes, and the lines going all the way around the mouth (mostly that bit under the mouth). Another tip to making a 'tough' looking character would be to go for a more square-er face, especially in the jaws (widen them and making the angles of the jaw, sharper).
Hopefully this will help some :-/...

Thanks Gigandas - this is just a construction schematic, so the contour lines are there not to add character but just for me to establish a feel for the topology. By tougher I just mean not necessarily comedic or prone to caricature, as Don Knotts certainly is (not necessarily a tough character, but just some head with a very prominent skull which doesn't have any really exaggerated features). I'm hoping to find some way to establish the base for a skull-head from which I can get some sense of how to draw heads at different angles, but a Don Knotts head is kind of an odd one to start out with. I'd appreciate any help along the way with respect to anatomical correctness and perspective (digital alterations appreciated). The faster I can construct them without significant errors, the better.

I agree with Gig about tough guys often having a squareness of the face, that kind of hulking-brute look. But I think that wrinkles and such don't detract from a person looking tough; done a certain way, wrinkles and other imperfections can make a guy look wizened and tough. Clint Eastwood has had wrinkles for quite some time but with that squint of his he still looks tough as nails.

I'm really impressed by your dedication, comd. If you don't end up improving by leaps and bounds (good as you are already) I think it'd be some sort of cosmic crime. I can't really give you any advice on anatomy or such, but you might try asking Cloxboy about that - he draws tons of faces at all sorts of angles without references. IIRC, he did tons of anatomy drawings back in the day, so he might be able to guide you along the path to anatomical enlightenment. ;)

We must send Xiau back into outer space to train our drawing skills until the time she decides to use her godly powers and come back to brainwash us with her awesome artwork.. She's gonna take over the world , dangit!

o.o I love the lineart and the toning; and I love the hair. ^__^

wow! awesome!

I like this very much. The figure is shaped well, and I like that transparency.

Its all working again!

Secret service agent

wow!!! nice!

oh wow! beautiful! that hair is simply amazing! I like your drawings :) I swear you improve so much with every drawing!

Ooh, this is damn spiffy. The colors and that beautiful hair thing you got going on there are what grabbed me.

That hair really adds a big portion to this pic. I love all the positive/negative space designs its creating.

Very nice picture! I love how you paint, refining the details more and more with each revision.

She looks like a female body builder :p great picture, cindy.

Lovely, just lovely. She's definitely a "10".

it's pretty, sticking her tongue at the camera, who hasn't done that?

I like you Silvair. You draw well and seem like a nice enough person :). We don't have enough people like you around this site...

Agreed! I like your style a lot ^^ Please continue to draw more!

This dude is smart.

I keep coming back to this to look at the eyes. The whole thing works but I think the eyes are magnificent.

Yes yes, quite so. I would most assuredly agree.

Can I join your collab too?

Can I join? >:3

Oh ok, well that's fine then. :)

"I like how the right side looks like she has a man back with a big dent in it! Like her man back side was in a big bar fight one night because this one guy took all the pretzels and one thing lead to another and ole' half man back thought she should get up and do something about it but then the other guy had a friend who usually doesn't come to that bar, no he usually goes to the 4 U lounge, but he went there this time and when ole' half man back stood up he knew he had to have his buddy's back... his buddy was a man so his whole back was a man back, not like this lady's back, but anyway, so he saw ole' half man back get up to do something about something an he slammed her upper right shoulder area with an extra 4 inch lead pipe he happened to be carrying around, not his good one that he had in his coat pocket for something else, but his extra one. So that's what I like about this picture when I look at it."

I'd just like to ask Zack one last question here. Is this what you call, 'formal criticism'? Of course, you could be referring to criticism given to terracotta by people besides Axil. But I'm pretty sure terracotta's posts were in response to Axil. Although, I haven't had 50 yrs of experience myself, I've never heard of giving criticism in 'tell-a-funny-story' form in any of my classes. And I can assure you, if that were the case, I wouldn't waste my money or time on such an unprofessional school.

No. What I was agreeing with Axil about was the issue of sexual abuse re: his cartoon. His critique was informal and absurd. I do not consider the issue of the picture being finished relevant to an analysis of the motivation behind any critique, formal or informal, since critiques on finished pictures are just as legitimate as critiques on works-in-progress.

The absurdity of Axil's comment speaks for itself, and to imply that he was being meanspirited for pointing out flaws in a finished picture demonstrates to me a lack of understanding of the nature of artistic critique in a learning environment. That is to say, Axil may have been meanspirited in his comment (I can't tell), but that has nothing to do with the fact that he was criticizing a finished picture.