21. First off, let me say, while you may have unintentionally deviated from the reference in terms of color, Id say that the values are more than likely spot on, and the colors you did pick are very pretty. My issue with this one is that the brushwork and shapes seem a bit... unfocused, for lack of a better word. There isn't a logic to which edges are hard and soft, and why in the lights. In the darks, the soft and lost edges make sense, but in the lights, the mismanaged edges make it more difficult to discern the clouds' form. 22. Apply the same praising of values to this one. I think, and I could be wrong here, that you, knowing that the light families were the focus of the painting, laid in the darks with a big, soft, probably round brush, and then used smaller and finer brushes to paint the light families. This is a good approach, but the shapes feel, again, unfocused. The shapes don't feel designed, but more circumstantial. There's no real rhythm to it. The big light shape in the center of the canvas doesn't feel like an intentional big ol' light shape, but rather a bunch of tiny shapes glued together. Also, the cloud in the upper right hand corner seems to be lit from a different, direction for some reason? 23. Again, values good, seemingly unintentional scribbly brushwork could be improved. As a guy who works in digital, the thing that sticks out to me is the odd yellow highlight. Now, don't get me wrong, yellow in a cloud is perfectly fine, but the problem is that the apparent value seems to darken where the yellow hits. I imagine you took a yellow colored brush with a layer modifier attached (not sure which one) and painted it to indicate some warm light hitting the very top of the cloud. However, in effect, the yellow comes off as cold. (For reference, a warm yellow has more of an orange tint, while cold yellow has more of a greenish tint.) In the future, I'd recommend a brush set to overlay for that purpose, or using a warm off white, with a sort of reddish pink as a halftone. 24. The clouds in this one are pretty darn good. Values are solid, colors are harmonious, brushwork seems intentional. I think you could have gotten away with exaggerating the darkness of the foreground to draw attention to the clouds, but that's more of a composition thing and not a study thing. The other far more major problem is that the clouds are lit from the wrong angle. They're supposed to be lit from behind, if they're in front of the sun. (Keep in mind, the sun is millions of miles away, so clouds will never be behind the sun in a scene where the sun is in frame, see attached reference by Julien Di Majo) 25. First of all, if it works, it's not cheating. Doing something like that won't help you learn, necessarily, but it'll fly in a professional setting. However, I agree that the way you've done it does create an odd, unintentional effect where the surface of the water is perfectly, uncannily still. However, this isn't a set rule. For example, in "Here Comes The Flood" by Magical Realist Rob Gonsalves, the surrealism of that is the point. Also, you can flip the canvas, and then come in with a hard brush to form the ripples. Overall, I think that a good exercise would be to limit yourself to one or two hard brushes for at least a few studies.