Most of the project management mistakes I’ve made over the years are due to a lack of concentration. The truth is, when things are running smoothly or when you’re diverted by other priorities, it can be easy to take your eye off the ball. I often mistakenly thought that even if things got a little out of shape, there would still be plenty of time to catch up.I asked some IT project management colleagues and a couple of professional rivals to divulge their professional gaffes. Here‘s a selection of their confessions and what can be learned from each one.

This information originally appeared in the article “True confessions: What’s your biggest project management mistake?,” by Patrick Andrews. It’s also available as a PDF download.

#1: Pay attention to details

“I realized that I’d been sending e-mail updates to the client and spelling the name of his company incorrectly for a month.”

It seems comparatively unimportant, but to that client, the error is a sign that you don’t recognize his corporate brand. Oversights like this will cause significant, unnecessary friction.

#2: Don’t mess up the simple stuff

“At my last company, I accidentally overwrote the data files for an online project plan, leaving me to re-create large parts of the plan from scratch. I couldn’t believe it when, later that year, I lost two people’s month-load of work because I was using an unfamiliar, source-safe revision-control package — with the wrong settings.”

The moral is to make sure to be professional even when you’re doing simple stuff like backups.

#3: Stay on top of schedules

“I simply forgot about the longstanding vacation plans of one of my crucial team members when working on the project plan. Fortunately, he managed to reschedule, but I’m still having to buy him beers just to keep the story quiet.”

See the previous advice — the same comment about professionalism applies.

#4: Don’t second-guess the right decision

“Last year, I was asked by two of my most respected developers if they could take a two-week training course. I had to refuse them, I thought, due to our departmental budgetary situation. They left the company, citing my lack of management ability as one of their main reasons.”

Maybe this manager could have handled the situation better, but you have to make decisions and live with the consequences. There’s no point agonizing about “what-ifs” after the event.

#5: Don’t pretend to know what you don’t

“When I was quite new to project management, I was embarrassed to admit my lack of experience in building embedded versions of programs, which I was pretty familiar with. I thought, ‘How hard can it be?’ It turned out that I had to work double-time just to stay in touch with what was happening on the project, and it resulted in a major cost overrun.”

Try not to get overconfident; that can often result in a major egg-on-face scenario.

#6: Don’t be afraid to admit your limitations or ask for help

“I recently found that one of my projects on behalf of a defense contractor was beginning to slide, but I was unsure what to do about it in a very macho culture where any admission of a mistake would have caused me to lose respect.”

The best way to lose respect is to allow your project to mess up. Every day you fail to communicate makes the task harder. If you have this problem, get it out in the open today.

#7: Learn to say “no”

“My CIO once goaded me into taking on another project when I was already really working at capacity. I lost focus, and a more important piece of work was compromised.”

This is such a common error because most everyone needs to learn to say “no” constructively.

#8: Don’t accept blame for another’s mistakes

“A senior manager asked me to put together a feasibility study. After I’d written a detailed plan and discussed the work with several senior developers, I discovered that the manager didn’t have an authorized budget. I was accused of wasting scarce resources.”

Carrying the can for someone else is unfair. Perhaps the manager will see this and cut you some slack the next time you need a favor.

#9: Forgive yourself and do better next time

“When I was asked for an unscheduled progress summary by my CEO, I panicked and left out a word in my e-mail response. The whole thing was misinterpreted and blown out of proportion. Even though the work was completed on time, I’m sure that my professionalism is still in question a year later.”

Don’t let personal history deflect you from making the next job your masterpiece. To err is human — even in project management.

#10: Don’t underestimate people issues

“I had a project that nearly came apart because I underestimated the impact of people issues within the project team. We had quite a few new developers, a few more experienced folks, and several contractors. The existing folks were part of a strong union and had adopted the “work to job description” mantra, whereas the contractors generally did whatever it took to get their deliverables done. This created a lot of tension within the team as the staff members felt the contractors were overstepping their bounds (and really they were, in order to get stuff done), and the contractors felt they were carrying the “slackers” (and really they were, in some areas). A complete mess. However, none of it was obvious until the tension started to come to the surface. By then, the schedule was compromised and had to be reworked a bunch.”

Keep a better handle on the personal issues within the team. Ask more questions, more frequently, to get at them.

#11: Take nothing for granted

“One project I was involved in went down the tubes because I didn’t check that the executive in charge had actually read the technical spec he had signed off. He then instructed a design agency to produce a product that the client couldn’t use.”

Check that your senior management has read and understands the project documentation.

#12: Keep the end user involved

“After three months and many labor hours, we delivered a RAD business tool the end users never used because it didn’t provide the functionality they required. The tool was trashed and we had to start again. The second time around, I kept the user and other stakeholders involved, and we delivered a business analysis tool they could use and be proud of.”

Keep the user involved from beginning to end in a development project. It’s the only way to be certain you will deliver what they want.

Learn from your mistakes to prevent bigger ones

Even though it may seem as though the high-pressure field of IT project management doesn’t tolerate slip-ups, carelessness is fundamentally different than failing while trying to do your best. If you (or that rookie project manager you’re training) can learn from your mistakes, then you might be able to prevent big projects from spiraling out of control.