I generally approach interviews in the following way:
1 - Be yourself - they can smell bullshit a mile away. If you arent yourself, you arent natural, and you dont seem confident and will inevitably stuff up in the interview.
2 - Be personable - treat them like you would any other collegue or acquaintence. Of course this means being professional, but have a laugh with them, and crack the odd joke if you can. Bottom line is that it says something about you as a person if you come into an interview with this approach. Just about all business want people like this because they need to deal with clients daily, and need to demonstrate interpersonal skills.
3 - Demonstrate your abilities covertly - If you have gotten through to the interview stage you are obviously a good candidate. You know why you are good but do they? They may not ask you about specifics in your resume, so it might be hard for you to overtly say - "hey im a good leader cos I was a prefect in year 12". But what you can do instead is find ways to slot things in. For example if they ask a standard behavioural interview question like "What have you done to improve yourself" consider what attributes they want (things like leadership, teamwork, task management etc) and then find ways to demonstrate those. So you could say something like - "when I was a prefect I had trouble initially balancing my school work, so I had to better plan my time, and I found ways to successfully co-ordinated my responsibilities".
4 - Know why you want to work for them, and how the position fits into your career aspirations. They usually want people who know something about what they do, but understandably realise that your not going to know everything. So a good line is to say that you want to learn more about it. Be honest and say that of the roles you saw on their websites, this one seemed the most interesting - but that you still dont really know, and that you want to learn. Learning is a key thing for most firms - they want people who want to grow with them. Usually a good idea to allude to how you see them in terms of your overall career plan - but honesty is rewarded as they can smell bullshit.
I think generally the online applications follow a similar pattern, but the thing is that they become tedious after the 3rd hour youve been working on it. I guess so long as you have reasonable marks and you present a reasonable answer you should be able to get through. I think another important point is that if youve got through to the interview stage, they are happy to hire you based on your resume so you more or less have to impress them based on you as a person.
