You’ve been offered a new sales job (Congrats!) and now it’s time to talk numbers. While variable commission and incentive compensations are likely set in stone by the company, there are a few salary items that are worth negotiating. These include your potential base pay, flex time, and benefits.

Matt Bertuzzi, Director of Sales Research at The Bridge Group, Inc., shares a few tricks for getting the figures in these categories to tilt  in your favor.

1. Know the exchange rate

Before negotiating a sales salary, Bertuzzi recommends doing a little homework. He suggests visiting web sites like Indeed.com, Salary.com and Glassdoor.com. All offer insight into what past and current reps with comparable roles earned, or are earning. This will help clue you in as to whether or not your experience and track record are worth a premium. Remember, there is no negotiation without justification.

2. Figure out if on-target earnings are attainable

While in the interview process, Bertuzzi says you need to ask a couple of questions:

• How many reps at the company are making their target income?
• What is the average rep earning?

If the middle performing reps aren’t somewhere in the 90-percent range of their target, it should indicate to you that the commission structure is not well calibrated. Similarly, if you discover that most people at the company don’t hit their quota, take it as sign that you aren’t likely to either. With this information, think about if working at that company is really going to move your career forward. If the answer is yes, then continue in the interview process. If the answer is no, move on.

3. Bring your W2 to your negotiation

It may come as a surprise, but when interviewing, sales reps often inflate the times they’ve met or exceeded their quota. Bertuzzi says one of the best ways to back up your statement that you are top talent and deserve premium pay is with proof. And the easiest way to do that is to lay out your current or previous comp plan and results, and then show your earnings using your W2. Sales managers will be able to see real evidence that you have overachieved and aren’t exaggerating.