The answer is that you had to push characterization hard in the early part of the story so that your plot is driven by that characterization. That sounds fairly complicated, but if we look at a couple stories, you'll see what I mean:
We get a very good sense of the story from those first three panels; Vic is frustrated by the need to wait around for phone calls, and yet he's forced to do so by circumstances. Sure enough, the story concerns Vic's being forced to wait behind the lines for a phone call, but when he sees an enemy surveillance vehicle he battles against the men inside and wins, but still gets chewed out for not waiting for the call. The next time, Vic brings the phone everywhere with him so he won't be punished for disobeying orders, but at the same time, he destroys an enemy machine-gun nest.
The second story in the same issue (All-American Men of War #24, October 1955) only requires two panels to set the stage:
You can tell that Andrews will find plenty of excitement in his new unit and that the ending will find him loyal to his new unit (which indeed turns out to be the story).
This one you could go several ways with, and the one chosen turns out to be pretty good: Hearn goes into the army, and teaches one of his fellow infantrymen how to film him with the camera. Hearn performs incredibly brave (not staged) feats, but something always happens that makes the film unusable. As it happens, though, another cameraman caught Hearn's heroics.
The next story can be seen through the following two panels, plus the title: False Alarm Pilot.
New Lt. Ben Burton has terrific ability but he keeps believing he's defeated enemy targets like a destroyer and a sub, when actually they have fooled him into believing they were sunk. So in the end he makes absolutely certain he defeats the sub by forcing it to tow him (with pontoons) to his base.
In each case the ending is suggested by the characterization presented.
