I think one thing you could really pay attention to is the line weight of the character, i feel like theirs a lack of commitment of the weight distribution added to certain areas like for example the feet, one leg has a ton of weight on it and the other looks loose and sharp. One thing i could recommend about line weight is not to think to much about it when designing something, use it more as a supporting role or as a accent to help push the weight of the design vs just using it for interest. Hopefully that make sense 
One more thing, i wouldn't suggest putting detail from top to bottom. Just like painting, you use light as a source of where to direct the eye, same goes with detail, if you have a ton of noise going on in the feet, people will look there and not the face, if you have a ton of detail everywhere, people don't know where to look and the design subconsciously becomes a tiny bit dull, by pulling all the attention up to the top with cool little details and leaving the bottom as a rest point then people will be more inclined to look at the face which is the most important part of a character.
Just a few food for thought critques, other than that your doing good, keep chugging away 
