I'm an 18 year old artist who aspires to be a character designer. I really lack ideas how to improve on it other than the few informational bits I get from Aaron Blaise, character design forge etc. Anyways, any feedback on that or gesture would be great.
Looking at your human sketches, I can see that your lines need to be more decisive. Right now they are too sparse and scratchy and as a result, the figures lose a lot of form.
Try doing a bunch of really quick 30 second sketches as an exercise and push yourself to get the gesture down in as few lines as possible. Remember, you only have 30 seconds so instead of trying to get the exact curves and shapes of all the muscles down, focus on getting the dynamic gesture that the pose conveys.
The countdown can be intimidating tempting you to scribble down what you feel is right, but refrain from doing so. Take a few seconds to digest what you're seeing and then put it down as efficiently as possible. The first few will probably be terrible, but the whole point is to improve.
If you're unsure how to begin the pose, draw the torso first as a block that is bending in a way that conveys the essence of the pose. This makes it easier to attach the limbs and head around it as you can always use the torso as a point of reference to make sure your gesture and centre of gravity are always correct.
Eventually, the fewer lines you have to put down, the faster you can complete the rough sketch which allows you to later focus on anatomy and shading. Therefore I cannot stress how fundamental it is to improve line confidence for drawing in general.
I have to say your understanding of anatomy is very good, particularly the limbs. You've got their gestures down and despite the occasional loose form caused by the lines, they're often very accurate and in proportion.
Perhaps in the longer sketches you can start shading and really thinking about the details of your anatomy. I noticed some minimal shading in a few sketches here and there and it was looking pretty good but of course there's only so much you can do in the short time allotted.
Good job on some of those sketches though. I think the sketch with the woman holding out the sword with both her arms is a perfect example of more controlled lines and accurate anatomy. Do more sketches like that and you'll definitely get the hang of better line confidence.