The best technique that I've heard is from Ramana Maharshi, and that is: "Do not bother with what happens after you die. First, notice that you have no idea what life is. If you do not even know what life is, then focus on that. Investigate."

"The only thing you know is that you are. that existence is. Investigate that existence."

This advice fits perfectly with the Upanishads. Find your "beingness" or rather allow it in all its contradictory manifestations or its seeming unity.

It is probably not too wise to prematurely make a unity of what may appear to be discontinuous. In Zen, they liken that to placing another head on top of the one you already have.

You can do something, which is to be as real and as honest with yourself as you can.

Nobody has a clue as to what happens after you die or whether all talk of reincarnation is just a metaphor. Who were you when you were asleep last night? Who are you right now? It is not a thing. You can never find that which you are.

Your "not finding it" is the beginning with respect to yourself as you are.

Be careful not to fixate on the witness as a thing. It is no thing. What sees can never be seen. There is no place to stand.