By Anne Fisher, contributor

FORTUNE — Dear Annie: I recently had my annual performance evaluation. Like every other review in my career so far, it was — how can I put this? — excellent but mixed. On the plus side, my boss thinks I do great work, I’m conscientious and detail-oriented, and my ideas show “tremendous promise,” he said. (I’ve been promoted twice in four years.)

Then comes the big “but….” I missed a couple of important deadlines, because I took too long trying to improve projects that I thought just weren’t ready yet. Also, I find it really difficult to delegate anything. I’m leading a talented team, but I want to make sure everything is done right, and sometimes it’s easier to do it myself than to explain how I want the finished product to look. My boss told me I should “try to be less of a perfectionist.” But how do I do that, and still keep our standards and our productivity up? —Baffled in Brentwood

Dear BB: “When I hear, ‘you’re such a perfectionist,’ it’s never clear whether this is a compliment or an insult,” says Jeff Szymanski. “Usually it’s a little bit of both.”

A PhD in psychology, Szymanski is a self-diagnosed perfectionist. He is also executive director of the nonprofit International OCD Foundation. A longtime therapist, he led a counseling program specifically for perfectionists at Harvard Medical School’s McLean Hospital. Now he’s written a book, The Perfectionist’s Handbook: Take Risks, Invite Criticism, and Make the Most of Your Mistakes.

Szymanski starts from the premise that the P-word is a double-edged sword. Some aspects, like extremely high standards and a do-or-die work ethic, are the fuel that make organizations (and careers) soar into the stratosphere. But it’s possible to push all of these too far, and end up crashing.

You seem to be describing common symptoms of perfectionism run amok: Believing no one else can do their jobs as well as you can, refusing to let go of anything until it’s flawless, and consequently blowing deadlines that matter more to your boss (and quite possibly others, like customers) than a “perfect” project does.

What’s more, if you’re like most perfectionists, you’ve been functioning this way for a long time, so it has become second nature. “Adult perfectionists usually tell me that they were often late turning in term papers in college, and even homework in high school, for the same reasons they’re missing work deadlines now,” Szymanski observes.

“The desire to keep on making something better and better is terrific, of course,” he adds. “The danger is, you can get lost in your own head and forget what’s most important to your audience.”

But don’t be discouraged. “The fact that you’ve been promoted twice in four years shows that some parts of your perfectionism are working for you,” notes Szymanski. “What your boss is saying is, you need to tweak it a little.”

Here are four ways to start:

1. Ask for input from others. Begin with your boss. “Some deadlines are more flexible than others. You need to know which ones are hard and fast, and which ones have some ‘give’ in them,” Szymanski says.

“Then try showing rough drafts of your work to others, especially your boss, as you get nearer to completing it.”

Perfectionists usually struggle with this, he says, because “they want others to see only their very best stuff. But saying to people, ‘This is a work in progress. What do you think?’ can be enormously helpful in avoiding the tunnel vision that makes you miss deadlines.” Who knows, a little collaboration might make the final product even better. It’s been known to happen.

2. Set priorities. “Perfectionists tend to believe that everything is equally important,” notes Szymanski. “It isn’t.”

His book goes into detail about how to decide what you really need to hold on to and what you can trust colleagues to handle, but the point is to “pick the five most crucial tasks and keep those. Loosen your grip on everything else,” he advises. After all, it’s less about lowering your standards than it is about acknowledging that you have limited time and energy.

3. Hold others accountable. Szymanski has noticed that perfectionists sometimes insist on doing everything themselves because “the real issue, which can be uncomfortable to deal with, is that a subordinate is not doing his or her work, or is not making the effort to excel at the job. If that’s the case, you need to sit down with that person and make your expectations clear.”

Otherwise, he says, the more capable and productive members of your team will get tired of picking up the slack and start eyeing the exits — and you’ll end up doing all the work, whether you want to or not, a sure road to burnout.

4. Have more fun. Yes, fun. Perfectionism is often driven by anxiety. Yet voluminous research shows that “people actually perform better when they stop worrying about making a mistake,” Szymanski notes.

“Try consciously looking for what’s fresh and intriguing about what you’re doing. Enjoying what you do, while you concentrate on reaching a goal, will help you focus less on what could go wrong,” he says — which can, over time, stop feeding the fear and anxiety that keep many perfectionists from reaching their stellar potential.

Talkback: Are you a perfectionist, or do you work with one? In your view, is perfectionism an advantage at work, or more of a weakness? Leave a comment below.