Have you ever been faced with really tough interview questions and wished you'd known how to answer them? The interview seemed to be going so well and suddenly you are thrown a question which knocks you right off balance. If you don't give a good answer, you could easily blow your chances.

The key to giving answers to tough interview questions is to do your homework. Good preparation and solid knowledge of the company itself, the industry in general and what this employer is looking for this job will give you the raw material for your answers.

Then you just need to refine them to fit the questions.

Let's take a look at some common but difficult questions:

Why should we hire you and not someone else?

This is tough because you have to give a convincing answer without sounding too cocky. The job description and your pre-interview research should have shown you exactly what they are looking for.

The way to answer this is to prove that you are capable of providing what they want and to show that you have a USP or Unique Selling Point which sets you apart from the average applicant. And, most importantly, you should use one which will add a lot of value to the company. When preparing your answer, choose the skills, experience and qualities which show this and write down some example of each.

So it is not the time to be shy. You just don't want to sound as if you know more about the job than the boss. Unless of course you have been head-hunted to solve a difficult problem.

Taking the time to prepare a solid answer to this question will also help you to answer related questions such as why do you want this job? And what do you know about this company?

How do you work with a boss or colleague you don't like?

We've all had to put up with them and so this question is to see how you cope with difficult people and situations. Be careful not to get personal or make judgements. If you start to say negative things about a co-worker, no matter how justified you may think they are, you are stepping into dangerous territory.

So prepare a short, factual answer. Perhaps you felt someone was very unfriendly and decided to ask her to join you for coffee or lunch. When you took the time to get to know her, you discovered that she had a stressful family situation which made it hard for her to relax. By taking the initiative in being friendly, you found she was much pleasanter in return.

Don't use an example which really triggers you, as when you get in touch with strong emotions, it is easy to say things you'll regret.

How well did your last job live up to your expectations?

This is a little tricky, especially if you are leaving because the job did not measure up and you hated your co-workers. But a good answer to this question helps answer some other questions which are in the interviewer's mind. Why are you leaving? What do you expect here? Will you stay? What are your goals?

Your answer may lead on to one or two of these additional questions. So be prepared!

Give some positive aspect of the job, which did match your expectations, such as new experiences which helped you develop your ability as a secretary, foreman, teacher or whatever your job title was.

You could say that you learned a great deal, but wanted to use a particular skill more frequently and there was no scope for that. Alternatively, you may have expected to be able to move higher up the ladder but there were no opportunities.

Be truthful but also careful that you don't create a trap for yourself. If there were plenty of opportunities for advancement, but you were too busy clock watching or avoiding responsibility, you will probably be caught out.