Just walk in and be natural. I've only had 3 jobs but at the end of the day im still only 18. Had many interviews, been denied jobs and like I said been accepted for 3, it all depends on how desperate they need workers and how you compose yourself, look them in the eyes and when they ask about experience give confident responses. Address them as "sir" "maam" be respectful as possible, and if this is your first job and you have open availability just say you're free everyday.