Like another poster said, longer sentences with commas are fine, but don't get repetitive. And think about the sentences structures you choose as other layers with which to tell the story and express character and events, like brushstrokes on a canvas.
cramming too much into one sentence gluing more than one sentence together into one scramble syntax [wrong order of phrases]
There are rules. And there are lots of things that people think are rules that are not rules. The style guides disagree with each other. The "rules" are not the same now as they were when I was at school (which is why younger readers often think I use too many commas). So get a good style guide that you think you can work with, and punctuate according to that style guide's rules -- but check for ambiguity, because although good punctuation can eliminate ambiguity, nobody has yet found a way to do that with rules alone. And be tolerant of people who punctuate differently: they may well be working to a set of rules that has as much claim to legitimacy as yours.
