What do interviewers usually look out for in interviews? What if I stutter during an interview, does it mean I am scared or nervous? Will it count against me?

The interview is to determine if you would be an asset to the company.
If you're interviewing for a position that you are qualified for (and you must have met some criteria or you wouldn't have been granted an interview) the best advise is to remain relaxed and listen to the questions being asked and answer them honestly. Dress comfortably but appropriately for the position you're applying for. Imagine if you were hired and started immediately... you know what I mean?

I have interviewed many and if a person stuttered, I just took that as being nervous. Or if they explained that stuttering was a problem with their speech on a daily basis. No reason to discriminate.

Dress for the interview but not overkill. Find out about the place of employment, do some background work and find out what you can. Be informed.

Be honest during the interview. If your job requirements would need you to be available during weekends and holidays and different shifts and you know you cannot do that, be upfront and say you cannot. Do not promise something that, in a couple months, it is clear you cannot fulfill. Your employer will think you duped them and they wasted their resources on training you.

Do something for yourself before the interview. To boost your confidence. Even if it something simple like going to the salon and get your hair styled or your nails done (or do it yourself). Something that makes you feel good about yourself.

Take a deep breath before going into the interviewer and then relax and do not be anyone else but yourself. No canned responses to questions. Good luck to you.

"Be honest during the interview."

Conversely

If you oversell yourself they are unlikely to sack you after 2 months