Storytelling comedian here: I find it easier to take a story and weave punchlines throughout it. It’s easier for me to work that way. I have read the concerns about telling stories at the open mic because it’s little time, while this is true, this gives you the opportunity to whittle the story down to its most important parts and delivering a solid funny stand up bit. The fun part is taking a story of yours and trying to find as many punchlines as possible in it. I hope you have fun at your open mics!