The intent of this post is not to explain the technical particularities of how you may create a Dropbox shared folder, but to share a good practice that has been working pretty well for me after years of using Dropbox.
Since I started using Dropbox [2010 I think] I have invited a bunch of people to join the service —as we all know that Dropbox regards you for the new comers you bring to their site. Dropbox is one of those services that works better if everyone you know uses it, as happens with Facebook or Whatsapp.
For this reason, I decided to do the following steps when creating one-to-one shared folders:
Inside a folder named Shared I would create a folder with my name [Nono Martínez Alonso], and I would invite a person to join that folder. This way, the other person gets a folder with your name inside his/her Dropbox.
After inviting to the folder, I would just change the name of the shared folder to the invited person’s fullname. The other person will keep the same folder with your name on it.
With this two simple steps, the Shared folder inside your Dropbox becomes a Contact List of the people you know that has Dropbox, being able to drag a file to anyone in your list, anytime.