I think an important part of this look is to not rely on outlines. Outlines take up pixels that could be put to better use creating detail, shadow, and motion. Avoiding outlines means designing your characters in a way that allows important parts (e.g. arms and the torso) to be separated by value and/or hue, without need for outlines. With your character's hoodie, that might mean either colouring the sleeves another colour, or posing the character so that their torso is more in shadow (i.e. with light only on their shoulders and arms), so that the arms can be lit against it.
Having interesting poses and bright, contrasting lighting is also important. Dull lighting and a plank-like pose are not conducive to the style you're aiming for. Moreover, such posing doesn't communicate anything interesting about the character. What is the character like? How would they stand? How would they summon up their powers? How would they strike? Think about this. It might seem easier to do a dull standing/walking pose, but it's actually harder in some ways, precisely because it doesn't give you opportunities for interesting overlaps and playing with light/shadow. If a character's arms are stuck to their sides, then of course they're going to be lit about the same way and are going to blend into the torso. If you can pose them in another way, then light/shadow will create the contrast you need.