Welcome to the Community Forums @Maryplee.
Join some of the current conversations and this is a topic you can also find a lot of info about.
I haven't been stood up yet. Actually, once. But a repeat buyer who I knew was good for the sale anyhow.
Always try to coordinate meet-ups same day.
Always try to make location most convenient to you.
Strive for good communication before hand.
I give 15 min. If I don't hear from them, I leave. That's it. If I agreed to meet someone, it means we had good communication prior to that. So, I would check to be sure they're ok. After that, I move on.