Know and Sell Yourself (and your CV)
You can never predict every question that you will encounter, so make sure that you prepare a list of the important skills or points that you want the interviewer to come away knowing at the end of the interview. These should be tailored to the role you are applying for.
For example, if you were to apply for a job as a New Business Development Manager you could aim to mention the services you have sold before, a list of previous clients, key successes in gaining large contracts, your sales numbers for the last 3 months and your relevant industry knowledge.
You would then look at each question asked as a way of getting that information across to the interviewer.
Back up your CV
Each interviewer will have had access to your profile and/or CV, and expect you to relate to your CV throughout the interview. Be prepared to expand upon the points within, and know the key figures on it, as evidence of your previous success.
Make sure you can clearly and concisely describe your work history to date in 10 minutes, and be prepared to describe your roles, responsibilities and key achievements without waffling and seeming dis-organised. Employers often start off with the question tell me about yourself or talk me through your key achievements, and this will help tackle that first and quite difficult generic question.
Make sure that facts that you mention at interview align with your CV, and don’t contradict anything you have previously put on paper.
Assess yourself
Selling your strengths
Ask current colleagues and your friends and family about your key strengths and skills and note these down. Think honestly about what you enjoy in your job currently, and why you are good at those tasks.
Work those elements into your answers by thinking of work examples of when you have demonstrated these strengths. Assemble hard evidence (make sure it's clear and concise) of how you have gone about what you've achieved in the past - proof of personal achievement will put you ahead of the rest.
Be clear on your goals
Review your personal goals and be able to speak openly and honestly about them and how you plan to achieve them. Make at least one of these work related and explain why this job sets you in the right direction to achieve these.
Work on your weaknesses
Pay particular attention to how to deal positively with any negative aspects or weaknesses - especially from the perspective of telling the truth, instead of evading or distorting facts, which rarely succeeds.
Once you are clear in your mind on what you have to offer and why this is relevant, all that remains is to get fluent on answering interview questions and approaching interviews, and practicing.
See: Practice Makes Perfect