I recently discovered a interesting book on self hypnosis: https://www.gutenberg.org/ebooks/22814
> got rid of the few negative thoughts I had
generally, you should try to understand why you have these thoughts. try meditating. but if you are using suggestions or affirmations, then you definitely don't want to use any negative words. don't say "I don't want to be unhealthy", instead say that you want to be healthy.
> How do I start
start meditating and energy work (such as qigong) also, try lucid dreaming and astral projection. keep a diary. get a Rider-Waite tarot deck and try divination. the reason why you should get a Rider-Waite deck is that the symbolism is both correct and easy to read. you can find some resources on tarot at https://www.sacred-texts.com/tarot/
other forms of divination are also worth looking into. perhaps also get a pendulum (with a pendulum you might try dowsing as well). it might be worthwhile to look into remote viewing (a form of clairvoyance) and CIA's stargate project: https://www.theblackvault.com/documentarchive/category/the-fringe/remote-viewing/
some of the remote viewing stuff got published in IEEE Spectrum and Nature.
> "do what you feel is right"
> a gut feeling
this. you might feel that the truth just kind of "clicks"
> Akashic Records
Astral Dynamics by Robert Bruce (the book mainly deals with astral projection)
the Astral Dynamics book also has a few energy work exercises.
> but is a half hour a day fine?
for me 30 mins is bit too little. I have trouble keeping a regular schedule but when I meditate, I try to meditate for 30-60mins. but since you are doing it for manifestation, I would definitely meditate on it daily.
> Is it a problem if I can't visualize properly,
the Astral Dynamics book has a couple of tips on visualization. basically, you should use as many senses as possible (not just sight). also when you visualize, you don't necessarily see it in your mind's eye.
> should I be trying to clear my mind anyway?
an meditation session begins with relaxation and clearing your mind. after that, you should start focusing on whatever you are meditating on.
I would be careful when reading his works. I think he might lie and speak half-truths on purpose in his books.