We do know a few things about what Heaven, or the Eternal Kingdom, will be like from Revelation 21:1-225. It's not a huge amount but it's something.
We know there will be a new Heaven and a new Earth, which means the old order passes away. There will no longer be oceans. A new city, the new Jerusalem, will descend out of heaven from God, having been built ready for the Bride. This city will be the eternal home for the Triune God, the entire angelic host, the church saints and the spirits of men made perfect (i.e. the old testament saints).
We also know there will be no more death, crying, pain or mourning. God will dwell amongst us. The new Jerusalem will be incredibly beautiful, with precious stones everywhere, because it's where the Shechinah glory will reside. The size of this city is immense - some 1500 miles long, wide and high, with 12 pearly gates. There will be no Sun or Moon, the light coming from God himself.
The River of Life flows from God's throne through the middle of New Jerusalem, on either side is the Tree of Life that existed in Eden, which will now return, and gives health to the nations, ie. it prevents all illness.
I imagine being able to meet saints from all eras of humanity! Pursue all kinds of creative interests. Fellowship with the saints and praise God. So much that we can't even imagine.