Doing good so far!
On the first figure I think it's fine and actually could look even more dynamic with a bit more exaggeration.
Also, if you look at the reference, she's leaning back quite a lot and putting almost all of her weight on her right leg. On your sketch she is putting a lot of her weight on her right leg as well, but there is a considerable amount put on her left.
Correct weight distribution can help make your poses feel more grounded and natural. Drawing a straight line from the head to the ground can help with that.
I recommend watching "Dynamic Figures: Why Your Poses Are Stiff" by David Finch on YouTube. He will explain gesture like Marc did, but he will also go more in-depth about the importance of weight.
I'm not that good at giving feedback, so please take what I said with a grain of salt. Some things may be correct, some may not be. Keep on improving!