Getting a promotion: Sure you even want one?

June 1, 2012, 1:45 PM UTC

FORTUNE — Dear Annie: I’ve had my current job in sales for a little over two years, and during that time I’ve gone from part-time to full-time and gotten one promotion. I’m great at my job, to the point where some of my peers are urging me to go after a management position. I’d like to try, partly because I want to make more money (about 20% more than I made last year, bonus included). How should I make my case for a promotion? — Top Gun

Dear Top: It’s nice that your colleagues see you as a high-potential kind of guy. It could also be — is my cynicism showing? — that they are just tired of competing directly with you and would like to see you kicked upstairs so they no longer have to. In either case, before you decide whether to shoot for a management job, you’d be smart to take a close look at a couple of key assumptions.

First, are you sure you would make more money as a manager? “Salespeople who get paid largely in commissions often make more money than bosses who receive a flat salary,” notes Brian Tracy, a serial entrepreneur, executive coach, and author of a new book called Earn What You’re Really Worth. “Research the market in your industry and your geographical area, and find out the going rate for sales managers.”

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You may discover that it’s about the same as, or less than, your current pay. In that case, the best way to boost your income by 20% may be to supercharge your sales performance and increase your commissions and bonus — even if you have to jump sideways to a different sales job at another company to do it.

Another point to ponder before you go after a management job: Why do you think you’d be good at it? “Top salespeople do not usually make good sales managers,” says Tracy. “I’ve made that jump a couple of times in my career, and it is huge. The two roles are completely different and take very different mindsets. For one thing, salespeople are motivated by individual achievement, while a manager has to be focused on the performance of the group.”

Even assuming you could make that shift, he adds, you’ll need to convince higher-ups that you can. “What management skills and experience do you have?” Tracy asks. “You need to think through your qualifications for the job and be ready to spell out the reasons why you should be ‘hired’ for a promotion.”

Try to build your case as if you were walking in off the street to interview for the job, since in fact you may be competing against candidates who are — and who bring with them a track record of managing successful sales teams.

Then, don’t neglect to test the political waters. Going after a promotion is one of the countless situations where a mentor, preferably one who is higher up in the company than your immediate boss, can save you from a misstep you’ll regret later on. “There may be dynamics at work in the organization that aren’t visible from where you sit now,” Tracy says. “Lay out your argument for a promotion and ask for advice.

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“Be open to information that may surprise you,” he suggests. “Often when people do that, they end up saying, ‘Wow, I had no idea.’” Sometimes, as a result, they also decide they’re better off in the jobs they already have. That’s particularly true in companies, for example, where middle managers are more vulnerable to layoffs than star salespeople will ever be.

For anyone who has weighed all the pros and cons and still hankers to take the next step up the ladder, Tracy’s book is packed with useful advice on how to get there. One of the surest ways to move up, he writes: Keep asking for more responsibility and, when you take on extra tasks, do them quickly and well. “Few things are more important than a reputation for speed and reliability,” he writes. “Whatever it takes, treat every assignment you receive as if it were a test upon which your future career depended.” Especially in this still-shaky economy, it is.

Talkback: Have you been promoted from a technical or sales position into a management job? What was the biggest adjustment you had to make? Leave a comment below.