1) Don't bring the salary topic
Never ask about salary.
The salary topic will come anyway, so there is no need to rush things and sound materialistic.
Wait until the interviewer asks you about your expectations.
2) Do Not Get Excited
Even if you are satisfied with the offer, stay calm and don't overreact otherwise it could hurt the possibility of a raise in the future.
Always make the employer feel that you deserve more, not through asking but through hard work.
3) Don't Give a Figure
Try not to be the first one to suggest a figure.
If you say a number that is too low, you would lose money and the employer will think that you lack confidence.
If you shoot too high, it can cost you the job.
Ask them to tell you "what the previous employee was getting?" or "what is the range paid for this position?".
If they insist that you provide a number first, give a range instead (between this and that).
4) Show Your Value to the Employer
You need to show your value to the company and how you can contribute to the overall output.
Talking about your success in previous jobs is good but employers want to know about the change you will bring.
If you can demonstrate how different you are and show your worth, the employer will be more inclined to submit to your salary expectations.
5) Do Your Homework
Do salary researches before you go to the interview.
Find out the standard salary paid to someone with your experience.
Be prepared to use this information as needed.
If the employer suggests a number below the average, be ready to tell them that this is below the market's average salary.
6) Keep Your Financial Life Private
Don't ever request for a higher salary because you have to pay for this or that, or because you have a loan or whatever.
The employer doesn't care about your personal problems.
Remember, the only reason to ask for a higher salary is because you deserve it.
7) Previous Salary Does Not Matter
For you it does, but for not for the employer.
Most candidates request a salary that is higher than what they used to get because it doesn't make sense for them to learn less in the new job.
This is absolutely correct but you should never use this excuse to justify your expected salary.
You have the skills and qualifications necessarily for the job and that is why you deserve it not because you need to earn more than what you used to.
8) Money Has Many Faces
If you reach to a dead end and feel that there is no way to push that figure more, ask for other benefits.
Rent, transportation, mobile, school allowances, medical insurance, air line tickets are all worth money.
Add them to the equation before you decide.
9) You Can Handle More
Tell the interviewer that you have the potential to handle more than the actual responsibilities.
Offer extended duties and challenges as long as you can keep up with them.
Extended duties mean more money and show confidence.
10) Don't Sound Desperate
Even if you are, don't show the employer that you are desperate to get the job.
If you sound desperate, it will kill any hope of negotiation.
11) Control Yourself
Don't get angry or loose you temper if things are not going the way you want them.
The last thing an employer wants to see is an ill-tempered employee.
It could be a test.
The employer wants to see how you handle pressure or how would you react in an unfavorable situation.
Think about it: if you reach to the salary discussion, then most probably the employer has interest in you, so stay calm.
12) Conditional Increment
If you are left with no choice, propose an increment or at least a review of your salary at the end of the probation period.
Make sure the increment/review is documented in the contract.