A frequent problem is the tendency to change points of view (POVs) within a scene. Ideally, there should be one point of view per chapter. If that is not possible, then there should be a significant amount of action told from one character’s viewpoint before the reader is switched to another character’s perspective. If we know what one character is feeling/experiencing/seeing then we can only surmise the other characters’ points of view from their actions or their dialogue. This is where the ability to ‘show not tell’ becomes particularly important to allow the action to flow smoothly.
e.g. Character A comes home and is exhausted and suffering from a headache, Character B is anxiously awaiting the arrival of A because they are supposed to be going out to dinner.
A knew that there was no way he was going to be able to tolerate a noisy restaurant tonight and dreaded the coming confrontation. B saw A walk through the door and thought, “here we go again, another excuse for why we can’t go out”. (2 different viewpoints)
A dragged through the door, squinting and rubbing his temples. He immediately walked to the radio and turned it off.
“Hey, why did you do that?” B just knew that her plans for a fun evening were going to be ruined again.
There are many sites that elucidate this principle far better than I could ever do so, here are a few places to start: