When I was assessed for disability I took a support person with me. I had paperwork from my P'doc. I also took my stuffed polar bear with me.... because he really helps me. I stutter when I am stressed and have spasms.
My support person knew me well so she answered a lot of the questions. I was very stressed so I wasnt able to control myself. I was granted disability payments.

You shouldn't need to fake things. I find the suggestion that you stare off into space deceptive. If you don't do that normally, don't do it. If they realise you are faking it they will be less likely to grant you the disability allowance.

Take some-one with you that can support you and also validate your claim for disability.

Good Luck.