About your first question, the more relaxed that you are, the better, because your subconscious mind will be more receptive to the instructions (affirmations) that you repeat to yourself. So I would suggest you to try to be as relaxed as you can before starting the auto-suggestion treatment. That is what the breathing exercises are for: to relax yourself.
In my case, after doing auto-suggestions (and self-hypnosis) for quite a long time, most days I don’t feel the need to do these breathing exercises, because I can get relaxed quite quickly.
Regarding your second questions, saying the affirmations aloud is always more effective. And you would also be hearing yourself speaking fluently (and therefore creating new fluency memories). I would say them when you exhale, in a soft voice.
Once you’re relaxed, you can say your affirmations normally.
Finally, your last question: the “proper” auto-suggestions treatments are the ones that we recommend to do at least twice a day: once in the morsning, when arising, and the other one before going to bed at night. Why? These are the moments when our subconscious mind is more receptive. But when I was a PWS I used to do another one during the afternoon.
These auto-suggestion treatments should be done this way: first of all, we must be relaxed (to achieve this state you can do the breathing exercises that we discussed here), then we simply have to repeat our affirmations aloud, each one at least 20 times. We also recommend to say these affirmations in a passionate way.
The idle-time autosuggestions are complimentary treatments to the ones I’ve just explained. These should be done whenever we have a negative thought, such as a stuttering fear. Let’s say that you have to make a phone call and you fear stuttering during that phone call. Well, before that, try to visualize yourself (visualization is very important both in auto-suggestion and self-hypnosis treatments) speaking fluently, confidently, calmly, while you repeat to yourself one or two affirmations (examples: “I love to speak on the phone”, “I feel very relaxed when I speak on the phone”). These idle-time affirmations help us reject negative thoughts and keep our minds full of positive ones.
Let me know if I’ve been able to answer all your questions, Khaled.
Have a great day!