Tiamat is everything that is of the Earth. Tiamat is a maternal "force" that can include components of good and evil, since it includes a cognitive system - man. God also includes this component, but it is of no consequence to Him. God is not able to be affected by man, rather it is entirely the other way around. But Tiamat can and is affected by man, even though all peoples are a subset of her.
Tiamat is more powerful than any person, or even than of all persons. But Tiamat should not be worshipped. It is important know that Tiamat is subordinate to God by definition. Tiamat is simply the Mother Earth, and can be thought of as all people on it. Just as individuals should truly accept gladly the Will of God, it is important for Tiamat to also accept the Will of God, if man is to survive as a race. But ironically, there is little that an individual can do about this except to keep their "own house in order." This is the best way to influence others in a positive way. It also serves to increase the amount of good in Tiamat, and to help her to accept the Will of God.
While Tiamat concerns herself with things of the Earth, she is not limited to only those things. Tiamat is Mother Earth, and her only intellect today is from human minds. She gains much of her heart from the collective human heart too, but her body is made of all earthly things and forces. But Tiamat is also affected by those things that are not of the Earth, and she must accept this fact. For example, without the Sun - which is clearly outside her control - She exists no more.
So too, must she always be comfortable by embracing non-human living systems. All those who live lives and think thoughts must be respected. How can one identify life? If it appears to live, if there is a possibility that it lives, then assume that it does. All of Tiamat must extend the same considerations to all living things.
Of course, God is unaffected by Tiamat and is not concerned whether she accepts His Will or not. God's Will is done anyway, no matter what. But for Tiamat to survive - for the Earth and its peoples to survive - Tiamat must be in accord with God. Consider this with every move you make. You are a part of Tiamat, and she is not asleep.