First off, the first piece is really nicely done! The hair looks so pretty, and the colors work really well together. That being said, I feel like the shapes are a bit vague. I think that working on a bigger canvas would allow you to add more details.
If you blow bubbles, you'll notice that they are essentially clear, but also reflective. So, in your piece, they would be the same color as the back ground, and have some highlights reflecting the foreground. Perhaps changing the background color to the bubble's light blue, that could really make the picture glow! :)
For the second picture, I love the hair! Clearly a strength for you :) The pose is also very cute. However, one thing that i think you could add is shadows. The shine on Percy's hair indicates strong lighting, so there should be strong shadows on the figures. I also like their eyes, but I think the couple would stand out even more if you added some variation to their face shape, noses, and lips. It might be helpful to you to go onto facity.com and try simplifying people's features.
I'm looking forward to more art from you! Let me know if you need any clarification on any of my comments :)
I have a burning question, what should I critique? I can give you these pieces of advice though. If you wish to endeavour in to the art of drawing I would suggest learning basic anatomy, although you have a preference for a certain style, if you lack the basics, you can not truly draw it.
What you want to avoid as a aspiring artist, is when you do a drawing two people, is give them to faces who are alike. Makes them look very unnatural. I would suggest doing some portraits. Learn how a face works, wich proportion a face has and what volumes make the face. This will help you in the long run too.
Developing a style means drawing a lot. You have got a certain feel for it, but it needs to be refined. Look how other artist approach the figure.
Now, I can recommend a few books you can read concerning anatomy and fun with drawing.
Fun with a pencil "Loomis"
Drawing from life "Bridgeman"
Dynamic Figure drawing "Hogarth"
i'm just saying that i like your sense of colors and it seems that you already got your own style.
i'm not saying that to search for the style more but just letting you know.
(please don't search for it or i'll be doing a mistake monition this point here)
otherwise i liked this artwork http://mbrandi97.deviantart.com/art/The-Nightmare-Before-Christmas-345936300
cause it got some of searching and efforts.
but you only need to work for some values and depth sense.
and i recommend this video as a support to help you with values.
so please watch the video to the and and let me know it's clear for you or should i give you some thing more detailed.