Yes, sandals were a bad thing. I hate interviews, and I suck at them too. You can't be too perfect. You gotta think of everything. How you look, your body language, What you say, and how you say it. Nothing can be overlooked. They scrutenize everything. They say decisions are made in the first 30 seconds.
definatly, what BB said. research the company. then you have a feel of what they are looking for, and you can formulate answers that are suiting. "what they wanna hear" Also, it shows you are interested and serios. I always have a set of interview questions I always practice before interviews. Preparing what your gonna say ahead of time really helps. I hate that question: what are your strengths and weaknesses. If I don't know what I'm saying before, I always go blank with that question. I bombed an interview for the shopping channel with that question, where all my friends got hired. My fault for thinking it was easy and not preparing.
I always bring an extra copy of my resume. Sometimes they are disorganised and it helps to give them a fresh resume for them to look at. If they say they are looking for somebody mature and responcible, with good math skills, try to answer then stating, how you are good with numbers, or you always show up on time. "tell them what they wanna hear"
yes, follow up. give a few days or so, and then call and inquire. Don't keep pestering them though. Also, as soon as you get home, send a thank you letter. This helps them remember you, and shows you really want the job, and that you are a thoughtful person. (good for hire)
I think it's good that you ask questions, but ya, don't boggle them down too much. Ask important things you need to know. NEVER ask about pay first. I always like to ask "what do you like most about working here" and "if you could improve one thing here, what would you improve" A good working environment is important to me.
I find the more interviews you have, the better you get. The most important thing for me is to be prepared. That's all I can think of atm.
EDIT: DJ just reminded me, when you find out you didn't get the job, ask them what you can do to do better at your next interview. Don't know if I agree on harrassing them that you seserve the job after they've already made their desicion, but there are a thousand answers to how to do interviews/write resumes, and they are all right and all wrong in some way, so use your judgment, and take our advice with a grain of salt.