For a start, you need to appreciate that the process of advertising, shortlisting and interviewing costs thousands of pounds per job, so take it seriously and don't waste everyone's time applying for posts you don't want or stand little chance of getting. Put in a tailor-made, well-presented application.
When invited for an interview, remember to accept it formally, and prepare well for it. You know the sorts of questions you'll be asked (Why do you want this job? How do you meet all needs within a lesson?), so think through answers and what examples you can cite to bring them to life.
First impressions count - look in the mirror. You are a teacher and are expected to look and act professional. Clothes and accessories should be smart and conservative. Don't distract the interview panel with too much reflection of your wacky individuality - leave that for when you've proved yourself to be an inspirational and top teacher. Schools want someone who'll be a good role model and team player, not someone who exposes tattoos and body piercings. On The TES website's virtual staffroom, a rather naive trainee teacher vented her outrage at being turned down for a job because of her tongue piercing.
People are usually offered the job straight after everyone's been interviewed and are expected to accept immediately. Asking people who are dazed and wrung out by the interview process to make an instant decision is tough, but that's how things work. If you accept, say that you're doing so "subject to a satisfactory contract and salary". Governing bodies can start you on more than M1 of the main scale in recognition of previous relevant experience, but you'll need to state your case.
Verbal acceptance is legally binding so you shouldn't continue looking for other jobs. Some new teachers accept more than one, out of ignorance or lack of professionalism. Play by the rules.