There are many different layers of the astral plane, none of them exactly easy to reach.
Mainly, when people discuss astral projection as a practice, they are talking about a form of meditation in which they enter sort of their own space and allow the physical world to fall away. The purpose is to detach and find inner peace and grounding rather than basing it on the material things around us. It is a practice of finding the edges of one's own spirit and how it is connected to the physical body. It can also be seen as energy manipulation in which one feels the energy of their own being and how that expands around them, then feels the energy of the space beyond that, almost like feeling and seeing by intuition or a very specific sort of feeling rather than by sight.
It takes a lot of practice no matter which way you are going about it, but it would be helpful if you could clarify exactly what you're trying to do with astral projection.