Well, it's important to have a clear idea of the character's personality and the mood you want to convey. Then, look at references from other comics or photos for inspiration. Also, practice sketching basic poses to get a feel for it.
To do poses well in a comic strip, start with simple and common poses. Pay attention to the balance and proportion of the body. Experiment with different angles and perspectives. And don't forget to add some exaggeration for visual impact.