There exists such thing as "more flawless"?

Interviewing is a skill like any other -- really a mix of both soft and hard skills. To be good at it, you actually need to practice. When I've been between jobs and preparing to interview, the first thing I do is re-read "Programming Interviews Exposed", just to recollect all the things that slip your mind about the process when you've been sitting at one desk for years. After I've done that I re-evaluate my resume -- make sure its current, that it reflects by best work and qualities, that it's still visually pleasing, contemporary (not to follow fads, just to not look dated), and highly scan-able. Then I prepare for the actual phone screen and interview processes by writing out answers for the types of questions I anticipate being asked -- For me personally, writing helps me collect and organize my thoughts. The idea is not to have a canned response for those questions, but to have my thoughts close at hand if I should be asked a similar question. I do this for both hard and soft questions. Everything from "Tell me the 3 pillars of OOP, and give an example of each", to "What's your favorite language and why?" to "Why do you want to work here?" to "What kind of compensation are you looking for". Questions of all stripes, usually between 20-30 of them. I also practice those logical brain-teaser puzzles that used to be popular (but have thankfully waned), and the type where you're meant to puzzle out a reasonable order-of-magnitude answer to a question you're not likely to know the answer to by inferences based on given or observed information (stuff like "Estimate the total number of K-12 students in the US" or "Estimate the number of gas stations there are in the state of California" -- lateral thinking questions), which I like a lot better than the former. I also code up a random sampling of whiteboard coding questions, and make sure I'm abreast of the latest programming languages, changes, and techniques.

Honestly, I think one of the worst things you can do in an interview is to take too long to start answering a question that ought to come out naturally. The only worse things are to lie to sound better, rush into the wrong answer, or to give one that's not been thought out at all. Being a dick in any way is up there too. But taking too long to think about straight-forward questions are the one that will get you turned away even when it maybe shouldn't (unlike the others) so its especially tragic to fail at it, I think.