I agree with anderson. Art is a very effective way to get to know one's system. If you've written in a journal at any point in your life and you're able to find it and read through it, you may begin to notice patterns of differing writing styles, handwriting and narrative voices (like when different characters in a book talk, you can often tell them apart by how the words they choose and how they structure their sentences and paragraphs.)

Since I was a kid , I've written songs and recorded them at home and looking back now, I can see who was doing what, how different parts of me think and express themselves and it seems they collaborate in different ways, too, which has shown how different parts are capable of communicating and working together. Recognizing those things has helped so much in a short time in working towards organizing the system and getting to know everyone. Without art and music, I'm sure it would've been much more of a challenge.

If you don't feel comfortable doing art projects or writing, trying to listen objectively to your own thoughts while doing different things you do every day may prove helpful. Is there a voice speaking in your mind? Is there more than one? Do they sound like you or like someone else?

Write down your findings (even just making lists or some kind of chart that makes sense to you) and keep them in a safe place where you'll be able to find them when you need to know something or you have some time to think about it all. The more you figure out, the more you'll figure out.

I wish you much success in getting to know yourself. It can be a grueling process but you're almost guaranteed to surprise yourself.