Let's make friends!
As a caveat, if you are a member of a monotheistic religion now is a good time to quit. Otherwise you're likely just to find angels and messengers of that faith and nothing else. If this is what you're looking for, cool: continue! If not, you will need to remove that outside influence that a monotheistic faith can create by quitting and moving on. Agnostic is a good choice, as are parody religions like Discordianism or just straight up going pagan but not choosing a god in particular.
So, you are cleansed and ready to make friends. If so, let's get started! If not then please click here for step 1: cleansing.
There are several common methods. I will list them in order from most reliable to least reliable.
Astral Projection
Meditation
Pendulum/spirit board
Astral Projection
Pros: Speak with and hear spirits on their own level, less risk of imagination overflow, allows two-way interaction.
Cons: Takes time to learn, requires understanding of defensive measures if something goes wrong. It's still wise to cross-check (click for how) everything you learn, just in case.
Step 1: Begin to astral project while awake (how? Click here!)
Step 2: Reach out and say hello
You will be using your astral form for the most part from this point on. If you are new at this, try "easy mode". Eventually you want to be able to do "hard mode" in order to work fully on their level for clearest communication.
Easy mode: Use non-verbal communication like waving to get the spirt's attention. Do not touch spirits until you have established communication with them as they may get frightened and lash out! A simple wave lets them know they are seen and can get their attention. Use your physical body to speak outloud. Greet them politely and listen for a reply with your astral self. Initally it may feel like just pulses of energy. This is them speaking. You may also hear a sort of whisper with your astral self in reply. You now can talk with them.
Hard mode: Remember the energy pulse communication I mentioned? You can do that, too. Focus on a message. Send that message along an energy pulse that moves towards but does not touch the spirit. Let the thought linger along with the energy. Let the words/energy slowly fade out, Sort of like how a ripple fades out in the water. Stop and listen for a reply.
That's it! You are now talking to the spirits.
Optional bonus: You may wish to leave small gifts of food or drink out near places where people walk by. It doesn't have to be much as it's the thought that counts. This allows free roaming spirits to come have a treat which encourages visitors. Don't leave things out longer than overnight. It can attract bugs. Discard all gifts once they have been out. Do not eat or drink them as it's rude to do so.
Meditation/Prayer
Pros: Great for working with gods-types and big names, less difficult than astral projection, requires less protection in general.
Cons: You will need to do this once a day/night until you get a reply (especially if contacting a higher power). Stay persistent! It took me eight months of nightly ritual to get a response when I first tried this method. Yours may be slower or faster but either way, keep it up. Will require cross-checking (click for how) to make sure it's not your imagination.
Step 1: Find a quiet space for at least one hour.
You will need at least one uninterrupted hour. No music, no phone, no TV. Nothing. Just you. You can leave the lights on if you want. Pick somewhere comfy as you're going to be there awhile Use the bathroom and get food first to help prevent interruptions.
If you are interrupted at any point, start again at this step.
Step 2: Clear your mind
Unless you are trying to reach a specific entity, you should have nothing on your mind. In fact, until you have started making friends and are very familiar with an entity, I would even advise against reaching out to anyone in specific because it's easy for someone else to come along pretending to be them, tricking you in the process. No thoughts is safest at first. Focus on your heart beat and breathing if you need something to focus on.
Step 3: Reach out and say hello
Focus on a single greeting. "Hello friends" is what I used but use whatever feels right. Either way let the thought linger. You are broadcasting it so your new friend can hear you.
Step 4: Listen for reply.
Clear your head as in step 2. This time, however, don't block out thoughts that come. If it pops into your head, write it down. It's OK if there is no reply yet. You may still move on to step 5 even if you got no "reply".
If what pops into your mind seems too mundane (ex: thinking about a song or TV show) it might be your mind wandering. Restart at step 1.
Step 5: Focus on what you need to know.
Focus on one or two sentences. If it's details about something (ex: image popped into your head last time) then focus and hold on just that one thing. If it's a question, phrase it as one clear sentence and hold on that sentence with it as the only thing on your mind. Let it linger. You are broadcasting it, as you did with step 3's greeting.
This is a good place to ask who is listening or working with you today.
Step 6: Listen for reply.
Basically it's step 4 all over again. This time, you should write down anything, even if it seems trivial.
Keep repeating steps 4-6 until the conversation is over or you are mentally exhausted.
Step 7: Thank them for their time
Similar to the greeting step, say "thank you" and let them know you are leaving now. Hold on that thought for a little while.
Step 8: Break focus
You are done! Feel free to cleanse yourself with a shower if you like.
Step 9: Send a thank you card (optional)
Ok, not a literal thank you card, but make an offering. It's basically like sending a thank you card when someone gives you a gift. The offering can vary and should vary depending on who you worked with, but most entities like having a candle lit in their name while a few words of thanks are said. Good quality incense is usually a safe bet as well.
Pendulum/Spirit Board
Pros: Super easy to learn, requires little in the way of materials.
Cons: Not reliable: cross-check (click for how) everything you learn every tingle time and take everything with a grain of salt. Requires physical materials.
Basic Pendulum/Board
Step 1: Construct a pendulum.
Literally anything hanging from a stable cord will work. A coin with a long string tied around it. A necklace on a chain. A fancy stone and silver pendulum. It all works the same.
Step 2: Find a quiet room with a stable surface on it.
A table in a room with closed windows, no fans, and no heater/AC running works fine.
Step 3: Hang the pendulum on a stand.
Literally any sort of stand where the pendulum can hang freely will work. If all else fails tape a pencil across the top of two tall cans. You just made a stand.
Step 4: Put a "spirit board" under your pendulum.
This can be as simple as a piece of paper. Draw a line down the middle of the paper. Write yes on one side and no on the other. Fancier boards may be used as well.
Step 5: Speak your question out loud.
Step 6: Hold your breath and watch the pendulum.
Holding your breath helps prevent false positives. Do not touch the table, stand or pendulun! With any luck the pendulum will sway over the part of the board the spirit is trying to use to answer (ex: yes or no).
Step 7: Thank the spirits.
Same as with meditation, some simple words of thanks, a lit candle, some incense and the like are good for establishing good will.
Step 8: disassemble your setup.
Put it away until ready to use it again.
Ouiji Board
Even less reliable than the pendulum. Tends to generate a LOT of false positives as you are physically touching the planchette. People tend to move the planchette without realizing it and blame the spirits.
Step 1: Get a Ouiji board.
You can simply put the alphabet on a piece of paper if you want. Write yes and no in opposite corners of the page. Put goodbye in one of the remaining corners.
Step 2: Get a plamchette.
Anything you can see through works. Magnifying glass, clear cup turned upsideown, a plastic bracelet, ect.
Step 3: Place the planchette on the board. Put your fingertips on the planchette.
Step 4: Speak your question out loud.
Relax your body as you speak.
Step 5: Allow your hands to move across the board.
Where the planchette stops will spell your answer.
Step 6: Say Goodbye.
This ends when either the planchette moves to goodbye or you say goodbye and leave the planchette resting on the "goodbye" space. Whatever first.
Step 7: Say thanks.
It's just the nice thing to do!
Did you have fun talking? It's now time for...