For starters, be on time.

Dress professionally. You don't have to buy a new suit, but don't show up in jeans and a golf shirt and sneakers either.

Don't chew gum. Yes, I had a candidate show up chewing gum.

Hygiene is important. Everyone knows about putting forth a tidy appearance, but there's more you might not think of. If you smoke, brush your teeth and wash your hands prior to the interview. Ciggie breath and ciggie handshake is a turnoff. It's not anti-smoker; it's the same logic as not wearing strong cologne, bathing prior to interview, or wearing clean clothes.

Most important: ask my questions honestly and directly and in less than 30 seconds (better if you keep it under 20). We get so many candidates that just ramble and ramble and give the used car salesman answers instead of admitting that they don't know. If you don't know the answer, say so and tell me you'd like to learn. I admire honesty and that's something I look for in a candidate.

We once had a candidate that stuck out in my mind because he gave the most canned answers I'd ever heard. He was very polite, well dressed, friendly, and everything we thought we were looking for. Then we asked him some basic questions like "Why are you interested in this position?", and he started rattling off stuff about lateral progression. We asked him to describe a specific example of how he improved a process and he instead talked about redefining progress. He couldn't even tell us how many years he'd been working. He didn't answer a single one of our 20 questions directly. As much as we liked him personally, we did not consider him further because we literally had no idea how he could be of benefit to us. He'd had an hour to tell us about himself and completely failed.

I learned later he'd applied for nearly every open position at my workplace and gave the same canned answers to everyone. I guess he was so focused on trying to work for us that the poor guy forgot that each position was unique.