>>394
The "secret", if it can be called that, is to practice in realistic situations and conditions. There tends to often be a "fear" among people to get enganged personally and going close up and having real experiences. But that is the most important aspect.
You do have to train your memory, and this can be done mechanically, but the exact method for this you have to find what works for you.
If you can already use telepathy, find someone to practice with (a spiritual being). If you can't do that, find some other "hands on" method which is close to, or aiming for, the real goal you have in mind.

I can only give the language learning example again. I've recently taken a course in japanese with the goal of being able to speak (very basic) fluently in 4 months. It sounds impossible, but it was doable. It was based off the first book in the series from this website, along with all the materials you can use on the site.
https://www.marugoto.org/en/
It's not very structured, and there does not really seem to be any method to the teaching either. But, as I did have one good asset I made use of that: a native japanese teacher 1 hour weekly.
Instead of trying to look good, or trying to do it right, I would "shoot from the hip" with the purpose of getting a feel for what is correct, AND more importantly making mistakes which the teacher can correct. That way I already made the initial mistakes in a setting where I won't lose face for saying something silly. And I also got corrected by someone who actually knows how to, and whose purpose is to give correct instruction.

Find an environment like this. I can only speak for myself, but I see making mistakes as the single most important element of fast learning.