The canvas size probably is not too small. The problem with adding details being difficult is what pixel art is all about. The goal is to abstract things into managable simple truths.
Adding details should always be the last step (not just in pixel art). First, start with the simple yet characteristic base shapes (for everything you draw or pixel), get that nailed down until you're happy with the pose and the overall shapes. Then proceed to identify the orientation of the base shapes by thinking of the figure as a collection of simple volumes, balls, tubes and boxes (practice that preferably in drawing not in pixels).
I blew up your pixels and drew over them, trying to adjust the pose a bit and in the process nudged things into simple and clear shapes. Not too happy with the proportions I ended up with myself (I think the upper torso is too long or the legs are too short) but might as well still share it to illustrate the general idea of aiming for clarity and simpleness first instead of going for anything overly detailed like trying to depict all the wrinkles in the cloth and cape, just pick a few important ones.