Avoid the progressive tense unless you want to emphasize the concept of "in the process of." A good rule is to use the simple past (fewer words) unless you want to emphasize the process. This may help: Prefer the simple past unless it doesn't work.
Last week on a writers' loop, a panelist announced, "Next month I'll be teaching at. . ." It would have been stronger if he had used the simple future tense and written, "I'll teach at. . . "
Here are a few from my students:
• Emily was making eye contact for the first time. (Was that an ongoing procedure? The author probably meant, "Emily made...")
• That day she was sitting at her desk, nervously shifting papers. (True, she stayed there, but doesn't it make sense to say simply, "she sat...?" The emphasis isn't on the ongoing activity of sitting but what she did while seated.)
• Josiah was seeing it for the first time. (He must have stared at it.)
• Gary was screaming at me to call. (My assumption is that Gary yelled one time.)
• Eli was whispering to a lean man. (This depends on the meaning the author wants to convey. In the context, the writer simply wanted to mention that Eli whispered something and moved on.)
• The goat was wandering free, dragging its rope. (What is the action the writer wants to emphasize? Dragging the rope seems obvious. Thus it's stronger to do it this way: The goat wandered free, dragging its rope.)