Jesus the Christ once said that the Kingdom of God is within you. This is Heaven. Yet, he also said that the path to salvation (returning to Heaven) is narrow and difficult.
There is far more to this life than the body we wear or the mind through which we see the world. Even the most positive mind is an artifact of this world and not of Heaven.
One valuable clue Christ gave us to solve this enigma is that the "first" (ego) shall be last (left out of Heaven), while the "last" (humble) shall be first (welcomed into Heaven).
In his Beatitudes, Christ said that the meek shall inherit the Earth. These meek are the same humble ones who are last.
But humility is not the only ingredient required. Christ also said that love is the first law. We must love each other as ourselves. Whatever we consider "important" for ourselves, we should give to others. We should loosen our attachments on what is viewed as "important," for such importances are artifacts of that which is "first" in the world and not of Heaven.
With humility and love, we must be fearlessly confident, even unreasonably so. For when we are confident without reason, we are opening the door to the spirit which resides in Heaven. This is our true self and, unlike the false ego self of this world, it is invulnerable, so there is no reason to fear.
With perfect confidence, we also need to take perfect responsibility.
When someone does something to us that is unpleasant and hurtful, if we take no responsibility, then we are a victim who blames the other person. If we take full responsibility, then there is no room for blame and we are incapable of being a victim any more. Thus, turning the other cheek becomes effortless. Forgiveness is automatic.
These are the things of Heaven. This is where it resides.