As a developer, I've had the opportunity to be an interviewer, and it's an interesting experience to be on the other side of the table. There are things besides sheer technical skills that I look for, and I don't often see them in the people I interview.
Interest in the company:
Are you truly interested in working here? Did you do your homework and find out about the company? Did you explore the website and find out what we do? Do you have good questions to ask? If the answer to these questions is "no", I'm going to assume you're not that interested.
Interest in the work:
If it's, for instance, a mobile developer position, are you excited about mobile technology? Have you written your own apps? Do you find it fun, and if so, why? I'd like to know that you'll actually like what you're doing, and it'll be more than just a job to you.
Personality:
Do you seem to be a person who's good to work with? It's ok if you're on the quiet side, but I'm looking for someone who will be compatible with the rest of the team and who will be happy to help others. If I sense that you're a prima donna, I'm going to be hesitant to recommend you even if you're positively brilliant technically.
Interviewability:
This sounds funny, but I wanted a category for an area that can cause concern. If you monopolize the conversation so that I have a hard time asking a question (once I practically had to ask a person to stop talking), I might suspect that you're purposely hijacking the interview to control it and to prevent me from asking questions that you might not be able to answer. If you do this, I probably won't recommend you. Let me talk and ask you questions. If you don't know an answer, say so. I don't expect someone to know everything, and I respect someone who is able to say "I don't know". It takes humility to be able to do that, and I like working with honest, humble people!
Those are some of the things I wanted to share because when we prepare for interview, we tend to focus on preparing for the technical part of the interview. We need to do that, of course, but we also need to prepare for the soft skills part.