You need to have some idea about what you are worth by knowing the salary of people with a similar background and in a similar position (ask people, or look up the salary survey).

You should postpone the discussion of salary and compensation to as late as possible. Giving a big number too early can simply scare the employer away. Later in the process, when the employer is more interested in you, you are more likely to get a good deal.

Although salary is the main consideration, you really need to consider the total compensation and benefits, especially when you compare several offers:

• 401k plan: availability, and employer match (employer match of 3% or more is not bad).
• Other retirement plan, such as a pension plan.
• Profit sharing, or stock option, or stock purchase plan. For profit sharing, ask how it is calculated to know if you can get more. For stock option, the number of shares may also be negotiable.
• Year-end bonus. Ask the range.
• Salary progression. What is typical for the first few years?
• Relocation package, if applicable.
• Sign-up bonus, if any.
• Tuition reimbursement, if you want to get another degree while you work at the company.

You job offer may have a job level (or grade) attached to it. Ask about the job level of the offer and discuss if you actually qualify for a higher level. A lot of times your compensation is associated with the job level.

The initial offer you received usually has at least 2000 to 3000 negotiation room. If the offer is too far away from your expectation (based on the job, your value to the company, and the job market), just say so and see how much better they can do.

You should not accept an offer over the phone. An offer is not official unless it's sent to you in a letter with company letter head. You should ask the employer to give you at least a week to consider the offer.

If you have other offers, you have more negotiation power. A job offer has a limit. When you tell the recruiter a higher offer from another company, and the recruiter won't raise the offer, you know you have reached the limit.

If you need your employer to sponsor H-1 visa and green card, and you have not discussed this, you definitely need to do so before accepting the offer. In that case, you need to select a rather big and stable company to work. Avoid a company who will (or may) go through re-structuring. If the company is bought by another company, or your department is spun-off and become a new company, you may need to start over your green card process.