Make sure you have read the job description thoroughly and you can give evidence for the skills they require. For the experience based questions, I like to prepare answers to questions I think they will ask, based on the experience they are looking for. I prepare answers that could be used as examples for more than one type of question.
If it is a programming role you have applied for, there will most likely be a coding test. Use online training resources like Pluralsight, which offers a free 10-day trial, to brush up on your skills. Or practice solving the problems in Project Euler.
For any interview, you should find out as much about the company as possible. Look through their website. Look for news articles relating to them. Try and get inside knowledge from any friends or family who work there. If you do know anyone who works there, try and get them to recommend you.
You need to show them you are taking this seriously, and you respect them. I always wear a suit for my interview. Don't forget to polish your shoes. Remember you are there to sell yourself to them.
Arriving 15 minutes early will show them you are keen. Don't turn up too early though, because if they find out you have arrived so early; they may feel under pressure to hurry up with their preparation work or finish whatever it is they're doing sooner than they want to. This will annoy them, so just try sticking to being 15 minutes early.
When you walk into the room, go in smiling and feeling confident. Give them a confident handshake. Make sure you keep eye contact with the interviewer and if there is more than one interviewer, remember to look at the others while you are talking.
I've never been to an interview where I wasn't allowed to take notes in with me. It shows you are prepared. You can write key words down to remind you of examples and scenarios to talk about.
It is crucial to be able to show the interviewer what you are capable of. If you are a web developer or designer, have a list of URLs ready so you can show them in the interview.
The interview is a two-way process. You are interviewing them as much as they are interviewing you. You need to be happy that if you were to get the role, you would be making the right choice in accepting it. I always like to ask at least three questions in an interview.
I would ask questions like:
When the interview is over, it is a good idea to ask if you could be shown around where you would be working. This gives you the chance to see what the working environment is like and allows you to picture yourself working there. This is also good because it shows you are keen and interested.
It may sound strange, but I enjoy the interview process. I like to have a conversation with other people I don't know, and I want to let them know why they would benefit from hiring me.
By enjoying the process, I can come across as warm and enthusiastic, rather than shy, nervous and withdrawn. It helps a lot when they need to pick between candidates who have the same skillset.