The only way to really understand what it's like to read another person's mind is to experience it yourself!
Here's something you can try that will give you an "inside feeling" of what it's like to actually read someone's mind.
I do this exercise at many of my Ladies Night Parties and other events.
Find someone you can feel comfortable with for this experiment. Decide who will be the "reader," and who will be the "subject." Sit directly across from the person and join both hands. Take a few deep breaths together. As you take each breath, picture your minds becoming closer and closer together. Now relax for a few moments with this image of your joined minds.
The subject is to think about something...a color, animal, person's face....something specific. The subject then tells the reader the category of what they are thinking about (animal, person, color, etc.).
The reader then relaxes and lets images flow through her mind, getting intuitive hints as to what the subject is concentrating on. Let the images, sounds, or insights flow together and take a stab at what the subject is thinking. Say it out loud, and check if you are wrong, close, or spot-on.
Then switch roles and do the experiment again.
This should give you a feel of how much information is going on in my own mind, when I am reading someone else!