holaa buddy, those studies sure seem to be helping out so i DEMAND that you produce more of them. Be mindful of rushing to get the colours down- are you starting with a pre sketch for some of these? The hands one for example has an odd finger on the hand on the left which throws the proportion and foreshortening a bit off (as well as leading the eye there!)
Always remember the more you flip and check proportions,accuracy and duplicity in the initial stages of your piece- whether thats a scribble,a blueprint or a sketch will make a fine outcome.
The stronger the start,the easier the ride.
Never Attempt the Possible;attempt the impossible and even if you fail,you'll fall among the stars.