https://line-of-action.com/practice-tools/figure-drawing practice from here a lot. draw with your arm and try to get the figure down. do lots of quick drawings and build up your library of poses and anatomy. once you feel you're good enough with realistic stuff start incorperating the art styles you like into your art and bang bada boom drawing yoai will come naturally and easy.
P.S try to do at least 10 drawings per 1 hour session, they can be crappy but try to make sure you're learning something even if it means knowing the mistakes you are making and making them
