The foundations and keys to magic are found in the imagination. It is not for nothing that the monotheistic religions condemn magic and imagination with the same firmness. They are not mistaken because to use one's imagination is to use magic and vice versa.
From a witch's point of view, imagination is always creative: everything we imagine comes to life in a dimension parallel to ours that is often called the "astral world". The more intensely something is imagined, the longer it will live in the astral and the more likely it will interact with the ordinary world, often on a psychic level, sometimes on a physical level.
This astral world is invisible to the physical senses but can be perceived by the psychic senses. For example: if I tell you to imagine a polar bear. This polar bear will exist for a short time in your head, but witchcraft gnosis claims that if you imagine this bear intensely enough, its smell, its color, its growl and the sensation it inspires in you, you actually give birth to it in the astral world. There, he will live his life in an invisible way, a life more or less long according to the intensity of your initial imagination. Imagine that you are walking on a beach. The wind is blowing in your face, you feel the spray and hear the sound of the waves, the taste of salt is on your lips. If you imagine this intensely enough, neuroscience shows that your brain won't know the difference from a real walk.
In witchcraft, if you visit the Great Pyramid or Ireland in your imagination, it is considered as if you are actually visiting these places... your astral body is actually visiting the astral reflection of the Great Pyramid which is just as real as its physical counterpart. Now imagine that you meet the Dragon of Origins, a god or a spirit. In fact, this meeting will begin in your imagination but will become real through imagination and soon a real conversation will take place between you and the spirit!
Imagination is not something subjective without any reality as in the expression: "it is in your head, in your imagination".
Imagination is in reality the perception of the world beyond material appearances. This mysterious, chaotic and prolific reality that we can see in the works of fiction, fairy tales, role playing games and mythologies of the whole world... (with the exception of monotheistic "mythologies" which owe their poverty to the fact that they only take over ancient mythologies by emptying them of their substance (Noah is only an impoverished resumption of the myth of Utanapishtim, the resurrection of Christ is a pale copy of the one of Osiris or Mithra, etc...).
Do not hesitate to train your imagination, it will be the key to your magical power, to your ability to contact the world of spirits and to travel to the other side of the veil. Train your imagination by reading works of fiction, by "animating" in your mind comics, comic books or manga, by listening to audio novels and by bringing the images to life, by doing jdr or by playing with your children. You can also move on to magical practices: shamanic journeys, visualizations, scrying.... the more your imagination will flourish, the more the other side of the mirror will be able to interpenetrate your reality and give it the richness it deserves.