I look for relevant experience, personality, and problem solving skills. I start off with questions that'll get me an insight into the person then I give them a written problem that'll take them 10+ minutes to answer. I want to see them work through it, see what they get stuck on, see when they ask questions and what questions they ask. I ignore syntax errors, and similar minutiae. If you don't have good problem solving skills I don't see how you can be a useful member of my team.