Often a mistake made by newer writers, head hopping is one of the most frustrating things to encounter as a reader. Its definition is simple--when the narrator switches between one character's point of view to another without preamble or a signal to the reader about the change.
Unintentionally distancing the reader is one of my biggest nitpicks. I make this comment continuously, and I think it's super important in most fiction. There are multiple ways to do fix this. Let's knock them down one-by-one.
Whether you plot or pants or some hybrid of the two, story structure is vital and necessary to your story. Oftentimes, pantsers complain, structure and outlines make me feel like I'm chained to a plot and stifles my creativity! And I once raised my voice with them. I hated the idea of structure, of beat sheets and outlines and all the other paperwork that it brings to mind. I stubbornly refused to use those resources even when I kept receiving rejection after rejection—not just from queries, but contests and potential critique partners.