First impressions are everything. Come up with a set of questions that you think they "might" ask you at the interview. You can google a list of popular generic interview questions and use that. Practice your responses in a mirror. Sounds silly, but allows you to gauge how you appear when answering these. Practice until you feel and sound confident. Confidence can make a huge difference in an interview.
Plan your outfit / appearance in advance, down to the hygiene stuff. Have a fresh and well styled haircut. Make sure your ears are cleaned out & your fingernails are clean for example. Try the outfit you plan on wearing on in a mirror before hand, and do your makeup & hair as if you were going to the interview that day. make sure you can repeat that process on the day of the interview. Make sure to dress professionally. It doesn't need to be a business suit or anything, but probably nothing less than business casual would be appropriate. Google "business casual" outfits if you don't know what that means.
One thing the military taught me that serves very well in the civilian world is that punctuality is appreciated, but showing up too early can also aggravate some hiring managers. 15 - 20 minutes prior to your interview time would be acceptable. Any earlier and it risks sending the statement to the hiring manager that you don't care about what time your appointment is, you want to show up and be interviewed on your own schedule.
If you had to submit a resume of any kind, bring a printed copy along with you just in case the hiring manager doesn't have access to a copy. (resume etiquette would be a whole separate "guide")
Since they want you to be proficient in using an Iphone, I'd suggest having an idea of some apps or functions you are very familiar with, and working out a presentation on how to use said apps / functions. Think of this presentation as if it were your portfolio and you're going for a graphic arts position somewhere. Get creative with it.
It's all about confidence matey. They obviously like the sound of you from your C.V. so you just have to prove that they're right and you're the person for the job.
Lots of eye contact, confidence, look smart and be prepared - take a good quality notepad/jotter and a pen and have questions for them prepared and make notes etc. to show that you're really interested and keen.
If they offer you a drink take a glass of water to help with the dry mouth
@(you need an account to see links) Also remember that a main focus of iOS is ease of use, and how the apple ecosystem is all integrated together. Since you're demoing an iphone maybe during the presentation you should show how the apps work together, and maybe also use Siri to your advantage. If I were you i'd go to apple's website and adopt that enthusiasm and faith in the iphone that they show in the videos. Pretend youre like Jobs at a keynote. Channel that energy and charisma that have people going wild everytime they announce a new product. Understanding how an iphone can become an important part of someone's life can help you also.
@(you need an account to see links)
oh yes sorry!!
It was okay i made like 1 or 2 errors
the interviewer didnt ask personal question like what kind of person i am/hobbies he asked more about my knowledge of apple products ^^
instead of demonstrating how to use a iPhone i had to demonstrate using iPhoto i kinda messed up there as i dont really use that software only for uploading photos xD