When I interviewed at Google several years ago, they told me up front that the salary was non-negotiable. It was very much a take-it-or-leave-it offer.

You may run into situations like this once or twice over the course of your career, but in most cases, there's room for negotiation.

In fact, I get worried when one of our senior hires doesn't attempt to negotiate their offer. That's actually a bad sign, and I start wondering how they're going to react when a vendor makes an offer. Will they just accept it without negotiating in that situation, too?

I know these negotiations can be anxiety-inducing, but there are things you can do to ease any nerves and put yourself in the best position to come away with a better offer.

1. Negotiate on the basis of what's important to you.

Your salary can certainly be important to your quality of life, but it isn't the only part of the contract you can negotiate.

In fact, most people I talk to don't name a salary as the most important factor in their decision to take a job. There are so many other aspects of compensation and responsibilities that can have a much bigger effect on overall happiness.

For some, a title is important. For others, it's the amount of ownership they have over their work. At a startup, many people value equity and upside potential the most.

Figure out what matters to you and focus your negotiations around that. If it happens to be salary, that's perfectly fine. Just realize it's not the only compensation you can consider.

2. Know the market ahead of time.

Depending on your career and industry, you'll want to be aware of the market dynamics at play when you're interviewing.

I worked in investment banking for two years out of college and then took some time off to travel. This was 2002, so when I began looking for work again, we were still in the midst of a recession. In that type of market, the labor pool for companies that are hiring is huge--and it can work against you.

I ended up getting a job offer to be a financial analyst at a well-known magazine. It seemed like a natural fit for me, and they gave me a week to make my decision. Unfortunately, I waited until the day before the deadline to tell them I would accept. And when I got in touch, I found out they'd given the job to someone else.

By dragging out my decision, I made it look like I was balancing different offers. I didn't factor in the poor job market, and there was obviously someone who seemed more eager to take the position.

Remember, nothing is official until the paper is signed. If you're going to take a role, let the company know you're really excited about it--and understand the market dynamics that may influence your negotiations.

3. Don't get too ahead of yourself with career planning and optimizations.

Over the course of a long career, a difference of a few thousand dollars won't matter as much as the more intangible aspects of the job.

What really matters is whether you like your manager, whether you like the company, and what you'll learn in this position. How is this going to help you get to your next role? It may not feel great to take a lower-salaried position, but if it puts you on the trajectory you want, then it probably won't matter in the long run.

Personally, there were times in my career when I took pay cuts because I wanted to pursue a more interesting opportunity, or I wanted to take a role where I had no experience. When I started working at clothing retailer Aé​ropostale after business school, I had no tangible experience in retail, but it was a way for me to shift industries. So even though my salary was lower than a lot of my fellow graduates', I took the job.

In my experience, the people who tend to make the most money are those who are really good at what they do. That comes from doing something you love and something that plays to your strengths. You should always negotiate your offers--just remember there are other forms of compensation than numbers on your paycheck.