On every job interview, comes the moment when the interviewer makes a reference to the salary that you will earn in the position that you are applying to. How much do you want to make is an important topic, however it is important to treat this subject carefully. To get some advantage in this area it is important, before the interview, to investigate the economic situation of the company (specifically, how much they pay people working in the position you are applying for) and preplan how you are going to respond to offers or questions that may be asked during the interview on this subject.
One of the possible questions related to salary, which can be asked by the interviewer, is "What is your salary history?" Behind this question, the interviewer wishes to know how your performance and how have you been rewarded in previous jobs. A useful answer on this case would be "My salary has been incremented gradually" which reflects an ascending tendency of your salary, however if the interviewer requires more details like dates and increment amounts, you could reply "I need to check on my records to provide you a more accurate information" if you do not have the specifics on hand.
Another question related to this subject would be "How much are you earning today?", and your reply should be honest in order to avoid any mishap in case they ask you for proof of your current salary. Finally the interviewer can ask you "How much do you want to make?" the answer should be simple, however it is recommended that you to try to make the interviewer present you an offer, with that goal in mind you can review with the interviewer the requirements and obligations of the job, then you could ask "How much does the company typically pay people in this position?" or "What is the normal range for a person with my skills and achievements?"
If you are asked to provide an exact amount for a tentative salary, you should be happy that you previously investigated the job salaries and companies that you are applying to, however do not mention your investigation with the interviewer, you could use a reply such as "With my skills and achievements I think I could earn (complete with the amount), do you agree?".
If the interviewer offers you an amount, which is lower than the salary that you used to have on your previous job, or an equal amount, feel free to immediately reply with a "yes" or "no" and rationale.