Thanks I’m very glad it’s useful! 
Our Astral Sense development collection has some homegrown tutorials for getting into trance etc.
Astral Dynamics by Robert Bruce is more for Astral travel but that also works the psychic muscles, as it were, and it’s a well explained and accessible book with a slant towards Western understandings.
I would highly recommend Remote Viewing as a psychic development tool as well. Controlled Remote Viewing by Lyn Buchannan (CRV) and Scientific Remove Viewing by DR Courtney Brown at Farsight (SRV) are the best. Lyn’s Book the Seventh Sense doesn’t actually tell you how to do it, but it’s motivating, as are the various interviews on yt with him that explain it very well.
Blind Sight is quite interesting and I’m working my way through this slowly: it’s about that art martial artists develop to see without using your eyes.