If you don’t see the answer to your question here, email it to me at email@example.com and I will add it to the list here (anonymously, of course). Here’s a post on what to expect the day of the interview itself.
Business cards – do I need them? As you apply to your first non-academic job, no. Thereafter you should carry them and use them if that is the norm in your job. If you have them in your current role, bring them with you if you normally would carry them.
Headshots – do I need a professional one for LinkedIn? No. The photos people use on LinkedIn range from entirely informal to professional headshots. If you use a photo, it should be good quality and should show you in a good light (not, for example, at a raucous party) but does not need to be formal. An employer is asking herself “would I hire the person who used this photo on a professional website?”
Interview clothing – what should I wear to the interview? When someone calls to schedule an interview, ask that person about the interview standard of dress. Most people are glad to be asked and will tell you. If you get a casual “oh, whatever is fine,” try to find out if anyone you know works there and ask. If you can’t find someone to ask, slacks, leather shoes, an ordinary button-down shirt and a jacket for men, and slacks or a skirt and a jacket for women are usually fine unless you are interviewing at someplace known to be more formal: if you are applying to be the office manager at a white-shoe law firm, for example.
Interview clothing, women – do I have to wear a skirt / suit / nylons / high heels? You need to meet the ordinary interview standard of dress of the organization where you are interviewing, which might include some of those things. Women are judged more harshly than men for deviating from this standard, unfortunately, so research is important here if you are interviewing for a job you think you would like. If you cannot find out, erring on the conservative side is usually wisest, which means a dark skirt or slacks, a relatively neutral top, and a jacket of some kind.
Interview expenses – will they be covered? If you have to travel to an interview, reasonable expenses will normally be covered: airfare and ground transportation, lodging, meals, and parking at your home airport. Not normally covered are, for example, roaming expenses on your cell-phone plan. If you are not given guidance about how much you may spend on meals that you eat on your own (after arriving on the night before the interview, for example) be careful to eat at some place reasonably priced and limit your alcohol consumption (or put it on a separate bill that you don’t submit for reimbursement).
If the interview is reasonably near where you live, you will be responsible for getting there yourself. Normally these expenses will not be reimbursed, though in many cities organizations will offer to cover your parking costs if you drive.
If the person scheduling the interview does not mention how you will be reimbursed, you may ask, e.g. “Will [organization] make travel arrangement, or should I?” If you are told that your travel expenses will not be covered, think twice about whether you want to interview with that organization.
LinkedIn – do I have to use it? In many industries and geographies, yes: in anything related to technology and on the west coast of both the US and Canada, it is expected that you will have a LinkedIn profile. Some fields do not use it at all. It is, however, rapidly becoming one of the sites of choice for recruiters, whose LinkedIn search tools are powerful. It is to your advantage to have a LinkedIn profile, updated with your current résumé.
LinkedIn endorsements – do I need them? No. These are clickbait designed by LinkedIn to drive traffic to their site and have never been used in a hiring decision that I know of. You do not need to spend time soliciting them.
LinkedIn recommendations – do I need them? No. They can be a nice-to-have, but given that they are not confidential and not vetted in any way, they don’t carry the same weight that a confidential reference does. You do not need to spend time soliciting them.
Skype / Google hangout screens – will I need to do these? Likely. More and more organizations are using these to do preliminary interviewing, which means you need to know how to use both and to practice beforehand. Make sure your area is free of visual and aural distractions, and dress neatly. If your work area is noisy (pets, kids, roommates, traffic), find a quiet space. Don’t use a coffee shop or other public space; the organization interviewing expects these conversations to be private.
Social media – do I need to purge my social media presence before I interview? Most organizations will not check and will not ask; if someone brings something to their attention, they may ask, at which point you should be able to explain the content they ask about. You should review your social media presence in advance of an interview and consider it from the perspective of your prospective employer. If you are interviewing with an organization that frowns on alcohol, for example, and your social-media presence is filled with photos of your multi-margarita Mexican vacation, you will need to explain yourself if asked. You should do a vanity Google search and make sure you can explain whatever comes up and of course explain anything on LinkedIn.