The first step in salary negotiations is figuring out what the job is worth in the broader job market. Your benchmarked figure will fit into a range that you determine by researching and comparing a variety of sources including:
opm.gov: typically grades 9-11 for Masters degree, depending on previous experience, calculates by location. Even if you are not looking at US Government work, these figures are a good starting point and will give a good idea of averages across sectors by location.
Once you have determined a figure or a range, be prepared to discuss your method of determining the range during your negotiation, i.e. "According to my research, a typical starting salary for an associate level Environmental Consultant for a medium sized firm working on government contracts in the NYC area is $x."
13 Tips for Salary Negotiations
Sell yourself in your interview (what makes you the best person for the job?)
Do your research about the employer and the position
Increase the value of the job with YOU in it! (the negotiation starts during the interview--help employer see you in the job and all the value you will bring to the organization)
Don't ask about salary during the interview or be the first to name a number
Benchmark ALL aspects of the position (job market standards for compensation, perks, title, etc.)
Know your personal job priorities (location, salary, benefits, value of experience)
Be prepared with creative alternatives to salary (flex time, bonuses, transportation)
Enter negotiations with a "Best Alternative to the Negotiated Agreement" or BATNA--i.e. don't be desperate, have an alternative
Keep interviewing and applying for multiple positions (will give you alternatives!)
Avoid bringing your personal life into the negotiation
Do NOT say "That is more than I expected!"
Use silence as a technique (employer may increase an offer if you don't respond right away)
The best negotiation is a Win-Win!
What Is Benchmarking? “Researching and comparing the broader job market’s standards for compensation, title, responsibilities, and perks based on the position, your skill set and qualifications.”
-- from Negotiating Your Salary & Perks, WetFeet
Calculate Your Take Home Pay
Online Resources on Salary Negotiations
“A negotiation is composed of two major steps: planning (research and strategy) and communication (information exchange and agreement). In the planning step, get as much information as you can up front and, using both the company's written and unwritten signals, map your skills against what the company values.”