For those unfamiliar with what this is, autosuggestion is the practice of “programming” oneself in order to achieve a goal; I have had personal experience with this goal in the past, as a matter of fact ages ago when I was a teen & this went partially well. Example:

Say you want to become thinner and lose weight; you need to write that down on a piece of paper and repeat that for yourself daily, with actual meaning behind it- so reciting it as if you mean it. I did this for general contentment and more self-confidence and it worked; I felt happier and became a lot more self-confident. Problem is that this faded after time and the process didn’t go smooth, as the change came off as weird and odd to others and I behaved that way too. I personally wouldn’t advise going ahead with this, it doesn’t really work to my liking looking back and also doesn’t work under stress/ duress. It didn’t work when I tried it the 2nd time for this reason. Things to keep in mind for the work is to keep your desired statements in the present, so “I am strong”, not “I want to be strong” or “I am no longer weak”…your astral body will focus on the “weak” part for the latter, so hence that. Also insert multiple fields, so not just one or two statements. Think of it as a small paper you need to memorize. That’s it. See here for more info on it.