I don't use a fixed list. I use certain areas that will expose their language to certain constraints. At this level, I'd start with a few personal questions to see how pre-prepared they were. If I suspected that they had practised their answers, I'd throw a surprise at them to knock them off that track. If not, I'd get them to talk about their current life, to see how they can handle present tenses, then go through things that would test their ability to talk about the past and the future, again based on themselves. This way, you'll also get a good idea about their vocab range, prepositional accuracy, etc. try to make it as much like a conversation as possible, but run through something systematically that will show what they are capable of.
For written tests, any basic writing task will do, but if you want to go further, then try some placement tests, like the ones OUP produce:
http://www.oup.com/elt/global/isbn/7160/
You can also try online tests if you like; here are some links:
http://www.usingenglish.co.uk/links/..._Online_Tests/
I hope this helps. I don't know if you are a new teacher opr what and don't want to sound patronising, but this is how I conduct interviews. I try to make it as natural conversation as I can, but try to ensure it has a structure that allows me to view grammar and, along the way, other language elements. I prefer this approach to the list of fixed questions, which strikes me as slightly pseudo-scientific and less natural. the more natural you can make it the closer to the truth you'll get. I'm not a fan of the tick-box approach and many will defend it as more accurate. Above all, let your own style develop. do what you feel is best, but have a reason for it. There are many roads to Rome.
suggestions?? + info 
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