Simple list, nothing complicated. As I've claimed before, I've developed telepathy from different methods, so here is a list of those methods, for anyone who's ever been curious. Ask questions, add your own, or debate anything I've said. I put it under Psionics because most people consider telepathy to be psionic, as opposed to magical or body energy arts.
1. Focal meditation. Continue learning how to focus until you can make it feel like you're able to push your focus outside of your head. Try a variety of things until you find something that works for you; I tried shouting at another person, "throwing" thoughts at them, and finally ended up building a firm mental tunnel from my head to theirs in order to push thoughts from my head to theirs.
Drawbacks: This develops sending telepathy but not receiving telepathy.
2. Void meditation. Just plain continue. At some point your mind will be quiet enough and you'll have paid enough attention to your mind that you should start subtly picking up on the thoughts of other people. There will be no "aha!" moment and will instead be a lot of "wait, why am i thinking of that?" and "wow, I was just thinking of that before they said that", which will eventually turn into "hmm, that popped into my head just before they started talking about it...". If you stop censoring your mouth, and instead start blurting out random thoughts that come to mind, then at some point other people should start saying "Wow, I was just thinking that" *a lot*.
Drawbacks: Takes a long time, progress towards telepathy is actually a side-effect and may never develop. Receptive telepathy only.
3. Pushing aside the Veil. Requires development of some sort of visual psychic perception. Reach out with the mind past your own veil, then simply brush aside the veil that hangs over others.
Drawbacks: Requires that you have already developed psychic ability/abilities, which means you've probably already done this naturally and didn't even need it listed.
4. Energy gathering. Continue energy gathering techniques until you can pull in enough that it feels like it is filling you to the brim, to the point where it feels like you are overfilling a balloon with air and the energy wants out. Pull it up into your head and keep pulling energy upward, holding it there. Do this for several sessions, getting a feel for the delimiting "edges" of your "psyche", and then push outward against the edges of the psyche even as you continue pulling upward from below.
Drawbacks: This is in bad taste as it attempts to force the energy. There will also be many other sensations, purely physical, purely metaphysical, and hard to tell between them: none of those other sensations *matter*, but some of them will likely be caused by (I'm guessing here) a blood rush in your head and increased nervous system activity (both of which are natural side-effects of focusing intensely on/near your own head). Try to adjust your practices as you go so that you do not hurt yourself.
5. Psychic Knowledge. Rather than developing telepathy itself, developing the ability to perceive "truth" in it's purest form allows for "fact checking" your own thoughts; this means that as you consider something, you psychically "fact check" it and receive psychic feedback as to whether it is correct or not (close ended answers). Pushing it to the next level, you learn how to receive open ended answers. Direct it towards another person and ponder "Is this person thinking <x>?" for the close ended questions, and "What is this person thinking?" for the open ended questions. A much more versatile skill than mere telepathy as you can use it for nearly anything, restricted of course by your level of development (especially useful for knowing when to shut the fuck up and go research a topic before talking about it).
Drawbacks: Temptation to stop using real world fact checking methods by looking information up properly. Not real telepathy so you do not perceive thoughts in real time. Receptive telepathy only.
6. Existing within the "Mental Plane", or whatever you want to call it. At some point along your practices, if you keep going far enough, you should come upon the psychic perception of partially existing on a pseudo level of reality that is "somewhat" (subjective term, others will have their own ideas on levels of intensity) skewed from physical reality. Probably most easily developed by either practicing over the internet, or with eyes closed. I would argue that this it not "real" telepathy in that it is not "strictly" telepathy, but since thoughts exist upon the Mental Plane it could also be argued that this is the purest form of telepathy.
Drawbacks: I know of no specific techniques for how to develop this ability in itself (others might know specific techniques). Can easily be confused with mere imagination if you do not properly confirm it.
Edited to put energy gathering technique under fake telepathy. I hadn't originally intended to create the fake telepathy group, and I had written up the energy one first.