When trying to communicate with Demons try to get in touch with their energy as much as you can. Meditate on their sigils, try to feel their energy, the more, the better. In time, while focused on their energy you will notice more things, more sings from them, guidance, appearance and in the end you will start understanding emotions and messages, you will hear tone of their voice...
If you learn how to tune in their energies it will be harder for enemies to make a fool out of you. Just remember how each God feel, what color of their aura is and similar.
When making strong bonds with certain Demons, it's much more easier to communicate with them. The more you are connected to a Demon, easier things will be. You open your mind to them, but still, be careful with those things, as lot of new people here are delusional in the beggining and sometimes even more open to the enemy than to our true Gods.
Opening to the Astral is beautiful thing if one knows what is doing. Important thing when opening those certains points on head and third eye is to keep practicing. The more you use them, the better they will become. Daily practice that means..