It's okay to lie a little bit. If you're telling the story primarily to entertain, people won't mind if you rearrange the order of events or leave out the boring bits.

Open with a hook. My style is to open with a deadpan delivery of the "punchline" without any context, e.g. "Quit my job today." This cultivates curiosity.

Keep the end in mind. I find that this avoids wandering. It helps if you've anchored the story by "spoiling" the punch line. We all have that friend who tells rambling stories that don't seem to have a point. That said -

Don't bogart the conversation. If you're interrupted, indulge the interruption, and bring the conversation back to your story if you can do so gracefully. It's easy to get fixated on your story, and to become irritated because everybody won't shut up. People detect this and it makes you look like an ass. Sometimes it works to get mock-irritated - "I was telling a story, dammit!" - if doing so feels right. Don't force it.

Don't get bogged down in quoting interactions verbatim. Nobody really cares what she said or what you said in what order.