Paradise through mortal eyes
Heaven is a broad name for a place that is outside of most human experiences. Some have gotten glimpses of it, but only the angels and the human souls in their personal heavens have any true idea of what Heaven is, or what it looks like. Humans in particular generally only get glimpses of their personal paradise and miss out on the true glory of the heavenly realm.
Personal Heavens
Worthy human souls that die come to Heaven, but each and every so rewarded creates their own personal heaven. Human souls have their own subdivision, if you will, within Heaven itself. These personal paradises are fabricated from memories and/or desires of the human, created even as they arrive after death. Angels can move in and out of these personal Heavens, sometimes watching, sometimes interacting, but the reality of these Heavens is whatever the human soul has crafted and an angel intruding in them tends to stand out.
Most of the time, the humans in their heavens do not even really realize that they have died. They might know it on some level, but this does not weigh on the conscious minds as they spend eternity doing the things that please them most and reliving their best memories.
The Throne of God
At the center of Heaven, with a view of the entire realm, is the long empty Throne of God. There is no angel that sits on this throne in the absence of the Creator, though if one looks carefully, there are two places at the right and left hand sides of the throne where the faint mark of feet are plainly visible. It is from this place on the right hand, the right hand of God one might say, that Michael makes pronouncements when he addresses the angels. The left hand side, most likely belonging to Lucifer, remains empty.
The throne itself seems to be wrought of gold, or possibly of light itself, and it changes depending on who, or what, is regarding it.
The Council Room
The Novarchy, the Nine Princes to whom God entrusted the world and all of his creations gather here periodically to speak and to make plans. It resembles a corporate board room, though is significantly more comfortable and richly appointed.
The Reflection of Eden
When evil was permitted into the Garden of Eden, God decided to lift its memory from the Earth and place it in Heaven. This Garden, is a world in and of itself, occupying a large section of Heaven, and is the most beautiful garden to ever have existed. Within its boundaries is every natural environment imaginable, all in their purest state of existence, fresh as it was on that first primal morning so long ago.
The Angelitic Demesne
Angels do not need to eat, sleep, rest, or fornicate, but they still have abodes, dwelling places where they can go to retreat from their brothers and sisters. Each angel has its own dwelling, small by mortal standards, but angels don't need much space either.