1. Create an email. Make it something very easy to remember. Never give this information to anyone unless you are dreaming.
2. Create a very easy to remember password. Again only give this out in dreams.
3. Attempt to get the person to wake up and email you the password immediately.
4. Make sure to change the password every time a shared dream has been confirmed.

When you receive an email from someone who claims you told them to email you, and they give you the current password you are using, you have just confirmed a shared dream experience. The actual details of the dream may be interesting, but they are not important. If not a confirmed shared dream, how else could you explain receiving secret passwords at a secret email which you never told anyone about outside of your dreams?

If you want personal confirmation simply follow these 4 steps, if you want to prove shared dreaming to the world, good luck!

Have fun. May your existences be long and enjoyable.
See you in the dream plane.