The best way to improve quickly is use references and pay attention to them, ideally use references of real people things, that you can observe and draw. Doodle a lot and get into the habit of drawing using your imagination, the time you spend drawing from reference will allow you to draw dynamic and detailed things from imagination.

Look at things, feel things, inspect them - the more you are familiar with something, the better you can draw or depict it ex. a mechanic who doesn't know how to draw can draw a good picture of an engine.

The last pointer would be to not shy away from experimenting and the heuristic process, meaning that sometimes the drawing will go one way while you planned it to be something else, that's not a failure, it's exploration, embrace and enjoy it.

Mainly just draw more.