I must believe in two things. That there is existence, and I have the capacity for experience, aka "consciousness".
My experiences however are not controlled consciously. I cannot imagine a cat in front of me, and experience all the sensations of a cat being there.
My mind feeds me experiences, presumably based on an external information that I interact with. I cannot prove such information exists independent of me however. I also cannot prove my mind's representation of any the apparently external information is accurate. Schizophrenia is great real world example of this. All I know is my mind is feeding me experiences, and I have no control over them.
I believe "God" is mind, and consciousness is the fundamental substance through which reality exists. Our conscious experience is one of infinite possible conscious states. All conscious states, of all scales and magnitudes exist equally, as a part of a greater unified consciousness, "God". Such a consciousness transcends space and time. The past is equally as "real" as the future, as both are possible conscious states according to their respective natural laws. The collection of all conscious states, of all times, all universes, all realities is what I would consider "God". It is not a being, it is all beings, all things, all that is possible.
For such a thing to exist, it must be infinite. If it was finite, then it could be added to. It must be whole. If you could subtract or divide it, then it would not be all of existence. Nothing can influence it, internally or externally, and it must be static. If "God" had desires or emotions, then it must change state, but a change from one state to another means you have multiple distinct states, and it would no longer be all that exists. If "God" was influenced externally, then there must be something that exists independent of all that exists, which is a contradiction. "God" must be static and unchanging, hence why the past, present and future all exist on equal footing. They are all examples of the infinite conscious realities that exist within the single, supreme consciousness.
Consciousness for me is the unified whole, "God", experiencing itself. Perhaps I can influence the path I take through the infinite web of conscious states, or maybe my path is set. All I can do is try, and I believe by seeing the world in such a way I am better equipped to confront any challenges that face me in this life.