Self-knowledge, or knowing thyself... damn, pretty hard topic to cover. I'll try anyway.
Problem with knowing thyself is that the what you seek to learn about... is yourself, the unique being that doesn't have a copy anywhere in the known universe. That is why really good tutorial on knowing thyself doesn't exist unless you yourself write it.
There are ways to go about it that can be taught, like psychology, biology, behavior study, and so on. These can give you some part of the picture. But that is not what you seek, I assume.
To go within yourself is a challenge that you can undertake in multiple ways. First quite interesting is exploring your subconscious mind through dreaming and lucid dreaming. Subconscious cannot speak with words, it speaks with symbolism. It can be quite advantageous to enter lucid dream in order to explore the "environment" of your subconscious mind, which means exploring without consciously changing the environment of the dream, that allows subconscious mind to communicate freely.
Another way is meditation, of course, you can use some imagination which is alternative to the lucid dreaming with the same goal.
Then there is that challenge of finding out who you truly are, to see yourself in truth, and dozen other decryption of that knowledge, that is also knowing yourself. Again, words come short, because even though it is knowing and seeing, while both being literal description, when you experience it, they fall short. It is a quest you have to go for alone. None can tell you how can you find out how to experience yourself this way. Experience is also another literal description of it... maybe it falls short too.
I cannot tell you what practice needs to be used to achieve this experience, only that you need to see through illusions, meaning to see through what you are not...
This know thyself is a quest, that takes years and even beyond lifetime to actually achieve and in fact it's never finished, because the world changes and we change too. Change is sign of life, after all. So this self-exploration is an infinite journey...