Toward Ecosophy

Yes, you need to finish developing your mental sheath into a mental body. You'll know this is happening when you experience your personality as a set of habits of thought and feeling, rather than mistaking it for yourself; when clear past life memories come through without any need to work at getting them; and when you notice that you've spontaneously stopped thinking in terms of this one life and naturally think in terms of a whole sequence of lives. (Another common sign is that reading books written from an enlightened perspective, such as the Tao Te Ching, gets a reaction of "well, duh" rather than "whoa, that's deep.")

As for practices, literally any of the standard spiritual practices will get you there, but meditation is the most effective. Now you know why I keep on suggesting it...