(1) I/You Ratio
The reality is, people don't care about you --- they are interested in themselves. So turn everything around from you to them--from sales presentations through to stories that start out "my wife/client did this". Instead draw them in by turning it around: "I'm sure you have a man in your life that did this (like my husband)" or "You would have met a client like Bob." Remove the focus from you.
Normally you would minimise details so as not to bore. But good stories have real characters and dialogue --- people think in pictures. So if you talk about a person, describe them. Give specific detail regarding time and location. For example "It was on a normal windy afternoon that you come to expect, living in Perth"; "She was so short with so many tassels hanging from her shawl you'd think she was a 1950's lampshade."
Your story will really come to life when you add dialogue. Instead of "he said, she said", actually rely what was said. You go to superstar status if you can even use different voices or if you were talking before an audience.
(4) Dramatic impact first
Your story doesn't have to start in the beginning with the natural progression. Why not look for dramatic impact by starting with a bold statement to pull your listener in, and make them want more immediately? You can start with the end or in the middle, then go back and fill in the details. If you were talking about a scary experience, your first words could be "I thought my life was over" (pause for dramatic impact) then go to the beginning and start the story.
(5) Where to find stories
If you're scratching your head wondering where you can come up with stories, believe it or not they are all around you --- in your everyday experiences, your past. They are lessons learned from parents and past employers, stories people/clients have told you and sales experiences.
So when you next need to be more persuasive or more memorable (to beat the pants off your competition) dig deep, grab a story, give it detail and practice telling it.