I think the hardest answer for people to accept about psychic ability and learning to use it is that the rules are simple: Be prepared to say no to whatever you feel you can't handle, but let go of fear. Let go of the noisy thoughts in your head, and prepare for someone else to say something. Tell the universe you're ready to sense, and mean it. Don't assume. Let go of your beliefs and get ready for anything. Pay attention. Shut the door firmly on your sensing when you want no more.
We can't explain to you how you'll sense things, because we don't know how you will do it. Everyone has a different way of expressing the sixth sense. You learn what yours is by practice. Practice is usually best achieved by meditating, getting used to always letting go of the noisy thoughts. At first, you might not realize anything happened; then you'll remember you just got a picture in your head, that you heard a voice, that you felt a sensation that didn't seem usual. And you'll think - is that it? Yes. It might just be someone communicating with you. You'll know for sure the more you practice.
Keep a journal of what you feel is psychic experiences. Read about other people's experiences, but don't assume their experiences and yours are just the same. What helps about reading other people's experiences is that you learn the struggle to understand is the same for everyone.
We are leaving behind us the days when psychics were only fortune tellers, when mediums were expected to be entertainment, when false practitioners took up the most space in the psychic world. The readers who used to fake psychic ability have moved on to pretending to be exorcists that remove the "damage" psychics do, because they figure that's where the money is. There will always be charlatans, looking for the money. What's important is that there are truly gifted people out here, professional and private, who are learning to just use the sense they have, and encourage others to do the same, no matter what level of gift or awareness. Turn to them.
That's all. Listen to the universe. It's ready to speak to you.