Anything you can observe around you is an entity. Any physical object, any person, any disincarnate spirit, any fictional character, any archetype, anything with any kind of coherent existence in the past, present, or future, in any kind of dimension, imagined, etheral, or physical - all of them are entities that have a consciousness of their own that you can be able to communicate with.
You don't really have to agree with the scope of this in order to use it. The simple practical part of it is that you can use communication to handle anything. You can talk with whatever has existence in your reality. There will always be someone or something around that you can talk with in order to gain information or improve the situation at hand.
At first that requires some imagination and a willingness to do something that other people might regard as crazy. Everybody talks to real live people; but if you start talking to the voices in your head, or to your car, or to your dinner, or to your teeth, or to dead people, or to your future selves, or anything like that -- well, that is different. But you will find that if you can get over the initial awkwardness of doing it, there is a gold mine of rewards to gain.
There is a whole field of principles, ideas, techniques, and modules related to spiritual communication with entities outside yourself. It is a path in itself to learn how to do it, to work through different areas and so forth. This is one of the things we can offer to clients as a growth path.
It is very freeing to realize that one can always communicate. One can always ask somebody, one can always work on clearing things up. And a lack of any appropriate physical person to communicate with is no barrier. One can telepathically or through imagination communicate with anybody one chooses to.
Objective validation is not necessary in order to communicate. If I communicate with a spirit who flies by who tells me all sorts of enlightening things that make me feel good, that is proof enough that I did something worthwhile. If many other people wouldn't believe it, or if I can't prove it with scientific rigor is completely immaterial for our purposes. Even if I am "just" imagining it, it still doesn't matter. What matters is that you have more information, that you feel better, or that situations change for the better.
If my car won't start, and I have a talk with it and find out it is angry because I didn't give it enough oil, and I give it some more and it starts -- well, it is the result that counts. My neighbor who doesn't believe in communicating with cars can stand swearing when his own vehicle won't start.
It takes work and practice to build up one's precision and confidence in communicating spiritually. One must be willing to be patient and work through disappointments and mistakes. One's trust will be established by repeatedly being successful in improving conditions through this type of communication.