There's a book called Hands of Light that's considered one of the foremost textbooks on energy healing.
https://www.amazon.com/dp/0553345397/ref=cm_sw_r_cp_apa_glt_fabc_DNCVFBZW4P8TYX9VPHHK
You might also look for a local school or reiki practitioner who will train you.
Feeling my energy makes it hard for me to follow visualizations because I'm always going "ok but what should I be doing with my energy when I do this"??? Lol my poor mentor, I've messed up so many things because I'm fiddling around with my energy while she's trying to work on me. I'm like a kid in a bubble bath splashing around and agitating the bubbles while she's trying trying to make a shape out of them.
How do you define objective here?
Barbara Ann Brennan's works, like her first book, Hands of Light on subtle anatomy and energetic dynamics, though not strictly condensed, are helpful in illuminating this subject. There are useful diagrams.
Barbara Anne Brennan has written a few books that cover all the basics, with diagrams. She provided the basics for me, and I took it from there.
> Can you heal yourself out of illness using astral projection or lucid dreaming?
Yes and no (you can disregard lucid dreaming). To AP at the same dimension/universe your body is (or the body of the person you are trying to heal), it's not a simple task, so, it can be done but is not very effective (from my personal experience). You'll be wasting too much time trying instead of actually doing it.
I'm a reikian, that means, we just redirect the "energy of universe" or literally, spiritual (霊) energy (気) and use it to heal. My friends that follow spiritism (mediums) told me I was born an "intuitive empath", they say I "work/function" as a emotional sponge. In my case, I have to be close to feel (physical empath) and also I'm able to sense things around (intuitive empath).
I've shared that experience with the group before, empaths tend to "absorb others people energy", what I do is to function as a rectifier.
Each and every reikian develops their own technique, personally I extract harmful energies, beam/pulse energy, clear the region, infusing and smooth the aura.
In my reiki practice, I absorb the negative/bad energy, convert that back to the universe as good, I can feel a flow of energy going away from my back (you let it go away as something good by setting your true intention) and replace that back with reiki energy in the person body.
Either way, it really doesn't matter the method or technique people use or develop, everything works with vibrational energy. Once you balance the person energy flow, their chakras, the body does the rest.
The longer you practice reiki, the better you get at it, what you can do to "turbo boost" that is to use AP to practice energy manipulation, to practice your vibrational state. For those interested in such a thing, look for the book Hands of Light: A Guide to Healing Through the Human Energy Field by Barbara Brennan there is a lot of exercises there to help you evolve in that area.
To the people interested in the science of that:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5871310/
https://pubmed.ncbi.nlm.nih.gov/24582620/
https://pubmed.ncbi.nlm.nih.gov/29551623/
The last one is a meta-analysis about the matter, it say:
Results: The result obtained after the final Reiki application was evaluated in VAS pain score. When Reiki (n = 104) group was compared with control group (n = 108), standardized mean difference was observed to be -0.927 (95% CI: -1.867 to 0.0124). Reiki was observed to cause a statistically significant decrease in VAS score.
Conclusion: Consequently, this meta-analysis revealed that Reiki was an effective approach in relieving the pain.
I do voluntary work in a hospital applying reiki, we are a group of 12 people, if they are allowing us to do it to this day, is because they are seeing results.
The video bellow explain about psycho-acoustic medicine, matter of fact, I've share some frequencies so people can practice this without prior knowledge.
https://www.youtube.com/watch?v=CnrPur7WKAA
Good luck.
The below links are a broad brush of some western energetic healing methodologies -
I highly recommend that you get a scribd.com account and download Max Feedom Longs Book on Huna - he does a decent job of explain how to use energy from outside of yourself - not your own "mana" so that you don't get sick when healing others.
Feel free to PM me if you have any questions....