How can you tell when the people in your dreams are made up or actual ghosts?

Dream figments have little substance or permanence. They'll be there, do and say more or less what you expect them to, and dissipate the moment you aren't paying attention to them.

"Real" entities have more solidity to them, more autonomy and coherence in their speech and actions. There will be the spark of sentience in their eyes, and they will persist whether you're actively paying them mind or not.

If you're encountering independent entities during dream states you've probably strayed onto the astral plane in your sleep. My usual "tell" for this is that the sky is an empty black void. Be discreet when you go to check, often the entities around me will become upset if I overtly try to go outside and see the sky.

I would try to identify these entities and assess their trustworthiness and their intention before doing them any favors; this represents an energetic exchange from you to them as well as possible shifts in the status quo that may result from your actions, all of which will obviously be to their benefit. Many astral entities are primarily interested in feeding, whether in the moment or securing a longer term "host" to parisitize, and are not above engaging in deception. Not to try to scare you, but you should be aware of the implications and risks when making agreements with an unknown entity.

this happens to me a lot, but i usually differentiate them through their intentions! my brain's very creative and i often lucid dream, so i try to find the simpler ways in identifying them c:

for instance, although you are dreaming, you may feel a pain in your chest or feel scared throughout the dream and you don't know why.

or, when you wake up you wake up with a strange feeling. if it has more of an effect on you when you wake up compared to other dreams, then that's a sign to re-evaluate what you dreamed about as it could just be the casual warning from a spirit or how you've been feeling lately.

most likely than not, when we are being asked something in our dreams it is usually our subconscious reminding us there are things that you need to do by creating people out of faces you could just pass by on the street.

if it is a spirit in your dream, there could also be something eerie happening. OR, the 'person' will appear out of nowhere and abruptly in your dream and you can just feel that they don't belong there. nightmares are also a common sign that either something in your life is plaguing you or a certain spirit/entity has decided to attach themself to you.

the more innocent dreams leaving you feeling a bit strange afterwards are usually spirits, meanwhile the eerie and more nightmarish ones leaving you a tad bit scared could be entities!

As someone who has weird ass dreams and lives in a family that we have a history with strange dreams that either sees the future occurances or having deep meanings that could still relate to the future occurances/consenquences. I once had a dream with my dead father, who usually I still think if most of them are just my brain still haven't get used to understand that he no longer is here (due of grief and longing) or if he sometimes would visit some of us (including me) to see how things are doing. One of the first dreams I had with him that felt really REALLY out-worldly, like I know it's not real but at same time I was aware that even if is not real real it still was happening, pretty confusing I know. I was in my living room, where the couch that my mom brought, would sometimes changes to the old sofa we had to the new one she brought, and my mom and my siblings we're there, except that, they seemed to not be noticing or caring that my father, shirtless and wearing a white baggy pants, was standing in front of the microwave, taking off what it seemed to be a mug full of milk? Which is weird since my dad don't usually like to drink warm milk, but maybe after his death he changed lmao. 

I knew he was actually dead, which I looked at him so weirdly, but when he looked down at me and asked: " Why are you looking at me like I am a dead person? " and I dumbfoundly answered: " Because... You literally are?!" and he straight up LAUGHED. I knew he was joking, but I couldn't help to be surprised that he even humors about it. We chatted a little, all I could remember is him asking how the things going, and I answered that things we're going fine and such and that we are trying to do better. The rest I cannot remember because my body in that dream felt like I needed to come back to my room, and my dad's face switched to a serious one when he noticed I was about to go, we didn't really said our goodbyes, it was more like I was coming back to my room normally and he just nodded and said his last words, which sadly, I don't remember too. 

After I went to my "room", is where I woke up. I was in distraught when I did, I felt different, strange. It was one of the most effective dreams I had with him, the first first one, is where I found him on his 20s, hugging me, where I for the first time, hugged him so tightly, in a way I never did when he was alive. It was after I reconciliated with God. I do believe that is possible and sometimes it can be just your mind messing it up, but also sometimes, it can be a spiritual connection with a loved one, or maybe someone that is connected with you, either in the past or perhaps in the future.

The world is insanely full of mysteries!

I've researched dreams a bit, for research projects and overall a deep dive, and what mostly came up as a common theme is we see people our brain remembers. You could see someone walking down the street one day and see them in a dream because even if you don't really remember seeing this person in your life, they can appear in dreams in such. Our brain itself doesn't forget a face.

There are many theories on why we dream, but no one has a definite answer really, even the most profound dream psychologists and researchers don't know. I think out of everything I've read and researched, I believe that we dream what we manifest. What our brain is constantly wanting (even if it's deep down and our conscious isn't aware of it), we can dream it. This is a fairly Freudian point of view, but this is how I see it—our brain's way of communicating our inner thoughts and desires.