Wow! You got alot of stuff posted in here! You may want to slow it down, give folks a chance to digest it a little bit.
It looks like you are coming along, I don't have much to say about the simpler studies. Your strokes are quite energetic, and I'd be careful about letting your finesse get in the way of taking in the maximum amount of information. Specifically on things like the still life with the vases. Sure, it looks good, but you may be sacrificing information about the light and actual texture for the effect. In the long run, you'll want to have control over that type of thing.
I think your general drawing / construction ability is your best asset right now, but I'm not altogether sure about the value lay-in. The cross-contouring is such a linear way of rendering I feel it's hurting the value read on your pieces. Are you being instructed in the same way, or is it just a way of working? Charcoal is a delicate medium, and I feel like you're making it harder by laying in values the way you do. I can't see a way for the midtones to come through like this, at least not without being just extremely good at handling it.
Similarly, when you work those strokes over different objects, they'll acquire the same texture and look confusing to the eye.
For your digital work, what resolution are you at? I'd scale up the canvas size dramatically.
For charcoal, try using a charcoal pencil and build up the values slowly, laying in a clear halftone, core shadow, and light side. I think you draw better than you render, but that's not a bad position to be in.
The largest problem with the rendering is that, especially with the fruit, you are loosing the subtle shifts in the form. Your shadows are really rounded, when in truth the shadows are pretty irregular. Unless you have an object that is perfectly smooth, like an egg or metal sphere or something, you want to pay more attention to whats going on with those shadows.
You may have to really change up your rendering process to deal with it, but in the long run, it will benefit you.
Another thing about the still life that Iruka included in her paint over that really lends an extra dimension to the forms is the bounce lighting from the plate and the cloth. The glossy surface of the fruit skin really picks up a lot of that white.
Posts
It looks like you are coming along, I don't have much to say about the simpler studies. Your strokes are quite energetic, and I'd be careful about letting your finesse get in the way of taking in the maximum amount of information. Specifically on things like the still life with the vases. Sure, it looks good, but you may be sacrificing information about the light and actual texture for the effect. In the long run, you'll want to have control over that type of thing.
Similarly, when you work those strokes over different objects, they'll acquire the same texture and look confusing to the eye.
For your digital work, what resolution are you at? I'd scale up the canvas size dramatically.
For charcoal, try using a charcoal pencil and build up the values slowly, laying in a clear halftone, core shadow, and light side. I think you draw better than you render, but that's not a bad position to be in.
You may have to really change up your rendering process to deal with it, but in the long run, it will benefit you.
DMAC's tutorial seems way applicable. http://forums.penny-arcade.com/discussion/comment/28450992/#Comment_28450992