There is already a lot of information on here about the video interview so I will not add to that. Use the information on here! Very useful. I was very prepared for my interview as all the questions had already been posted by another user and while I did not write a script or even come up with the answers in bullet points I had already thought about my answers to those questions. What I will do in my post is give some insight into the language ability test component since I did not find any information on here about that. My recruiter told me that there is nothing to prepare for it but had I prepared I probably would have made it through (I didn't). Obviously what you are asked all depends on the tester and to be fair they probably aren't expecting you to be on a native level but I think preparation would help, if anything to give you some confidence so you don't hesitate so much (if you are like me and are out of practice in your second language not having used it since leaving school quite a few years ago). I do believe that they are testing language ability rather than actual content of your answers but again, giving half decent answers would help with confidence and thus fluency. After this phone call you will have half an hour to find a news article (she asked for one in the area of the topic I suggested talking about) and produce a short summary of it in your tested language. Don't spend too long finding an article, I did that and didn't have time to produce a good summary (especially when I had to google translate very specific terms like IMF).

Begins with a personality assesment that also includes puzzles meant to test pattern recognition. The assesment and the personality quiz takes about 30-40 minutes and requires no preperation before hand.