In honor of academic interview season, I thought I'd discuss a few common pitfalls I see candidates fall into on campus. Way back when I was interviewing, I made some of these mistakes myself, so I know how common a trap it can be. For those job hunting, xykademiqz has a great post on advice for Skype interviews, some of which carries over to on campus interviews as well.
The research talk: A good research talk will engage both experts and non-experts for at least a portion of the talk. It will also demonstrate your technical and research skills to the experts. Thus, it must have both breadth and depth. This is where I fell down in my first year interviewing. The most common mistake is to focus too much on depth (I did this), but it is equally problematic to focus too much on breadth (I've seen this) and not come across as an expert in anything.
The chalk talk: The chalk talk is hard, because it is unlike anything else most people have done in the past. One major issue is in presenting a bunch of projects that look like just a bunch of projects. From years of experience, most postdocs are used to thinking about their research in a project by project way. However, in the chalk talk, we want to see an outline of what the candidate's research program will look like over time. Pretty much all of the candidates invited to campus had some long term research plans in their research statements, but this needs to come out in the chalk talk as well. Our department wants to hire someone who will have a successful career, and that means making sure that the planned research leads somewhere beyond the immediate 3-5 year project horizon. What will your lab specialize in? When we discuss our new hire, what is the one sentence summary about your work that we will lead with?
Related to this issue is candidates who position themselves in competition with their previous groups. It is great that you love your current (or previous work). It is great that you can take it with you. HOWEVER, unless you can clearly articulate the differences between your approach and your supervisor's approach to non-experts, some in the audience will wonder if you will be successful in funding your work. Towards that end, a really common question is "why would a funding agency give you this money instead of your more established adviser?". You need to have an answer.
The opposite problem (moving to a brand new area) can also be problematic. Without a track record, some will be reluctant to take a risk on a candidate. Also, proposals into a new area can come across as naive or not fully formed. Realistically, at ProdigalU we do consider the experience level of our applicants, so if one of three proposed projects in a new area comes across as naive or unrealistic for an inexperienced candidate, we are usually pretty forgiving if the other proposed projects are well done. This is particularly an issue for candidates trying to force their research to fit into a targeted job search, and it becomes obvious in the chalk talk unless the candidate is really interested in moving in that direction for the research's sake rather than just to get a job.
A final chalk talk issue is particularly common with those from large and well-funded groups. Really innovative research is a great attention grabber, but as a PI, you will have real students who really want a degree and therefore need to have some research success. You need to be able to articulate not just Plan A, but also Plans B and C for your projects, and also discuss what important (i.e. publishable) work will come out of your planned research directions even if the project is ultimately unsuccessful. There are no great rewards without risk, but you need to show some awareness of the other requirements of your research program (like that you will be training students, not just doing cutting edge research).
Personal interactions: Do not make flip or ironic remarks that could be misinterpreted (I did
that when answering questions after my research talk my first year
interviewing, and it was a mistake). Personal experience aside, every aspect of the visit is part of the interview, including the meals, the walks between offices, the interactions with non-academics, and the transportation to/from different locations! Be polite to everyone (including all staff members and students). Do not drink more than you can handle and remain in good control of yourself, regardless of how much your meal companions indulge. Do not make disparaging comments about pretty much any person, group, or place. Do not bring up politics as a topic of meal time conversation. I have seen candidates do all of these things, and it did not make a favorable impression.