When composing music, how to be influenced by a soundtrack (of films, video games...) without copying?

" An artist never works under ideal conditions. If they existed, his work wouldn't exist, for the artist doesn't live in a vacuum. Some sort of pressure must exist. The artist exists because the world is not perfect. Art would be useless if the world were perfect, as man wouldn't look for harmony but would simply live in it. "

Andrei Tarkovsky