Know your audience. If you're surrounded by a group of females, chances are they will not want to hear about your amazing late season comeback in your keeper fantasy football league.
Start with a bang. This is called the hook. If you don't grab an audience within the first ten seconds, you will most likely lose them forever.
Use only pertinent details in telling your story. Too much information adds unnecessary length. The average person's attention span is under one minute.
Avoid tangents and stay focused. If a part of your story entails you tripping over your dog, don't get distracted and start talking about how your dog got sick that morning.
Avoid repeating yourself. Chances are that people heard you the first time and a storyteller may fall into this trap especially if a segment of their story gets a big laugh. Nothing is more lethal to a narrative than repetition.
Respond to audience reactions. If you see people looking disinterested or in other directions, it's time to pick up the pace.
Learn from the past. It's important to recognize what aspects of your story got the most laughs or reactions in previous tellings.
Embellish as necessary. Most of your friends have already heard all your stories anyway. There's nothing wrong with a little enhancement.