Rosie and Vanill - Spirited Training

Let me get the simple part out of the way, before I go in depth: I like it, but I don't love it.

The roundhouse kick pose is accurate. From the shout bubble in the background, you can clearly tell that they're packing every once of their power into the kick, which is an effect you want to have! Making them tilt their bodies towards their right foot a tad more would've added a lot of dramatic effect, even if it may be less accurate.

The perspective is good. The horizon line is relatively consistent. The angled feet were a nice touch. It suggests depth. For the future, I'd like to point out that the kicking leg should be drawn shorter than the other leg to appear the same length. Its difficult to tell whether you made a mistake there or not because it looks quite normal, but for the future.

You have no idea how glad I am that you didn't shade in gray. The characters pop out from the background. That's a plus.

Here's the part that's slightly less friendly.

The faces could be improved on by adding cheeks. This is something many artists do not do, especially those who use circles as guidelines. When drawing a front facing face, you do not need to draw cheeks, and if you do draw them, you do not need to emphasize them. This is because cheeks come forward, so when looking at a face from in front, the cheeks will not pop out of the side of the face.

However, when drawing from the side, the cheek will pop because you are looking at the cheek sideways. Imagine looking at a carrot from above. You wouldn't be able to see the fact that everything meets as an apex, but when looking at it from the side, you would easily be able to tell. Getting the faces right takes practice, but it isn't hard to do.

Proportions can be improved on as well. (I'm not perfect at this stuff, I draw legs too long.) The legs are a bit too long compared to their upper bodies (similar to my build in real life, but more extreme). Considering these are Sonic characters, you could use canon images and then compare the size of the head to the body, the body to the legs, the legs to the head, etc. until you get the canon proportions and alter them to fit your characters. Vanill especially needs some tweaking because when someone is younger, their legs are shorter compared to their upper bodies. Proportions are really difficult, so just tweak until you get it right. (It is a lot easier to do these things on a digital art program, because you can alter the sketch a million times without it showing at all in the final project. On paper, there are smears, pencil imprints, the fact that you can't erase colored pencils and crayons, the list goes on.)

There's a tad too much blue, and its a little difficult to distinguish the sky from the ground.

I'm glad I see you stepping out of your comfort zone and drawing some poses that do not involve looking directly at the camera. Depth is a very important thing, and its something this picture definitely has. There are tiny issues that seem to be one time mistakes, and the others are easy to fix. Overall, I like it. I'm definitely seeing improvement.