This is a guest post by Nicole, winner of the competition for the best answer to the question: “How can you avoid being let down by other people’s poor time management?”
The only way to avoid being let down by other people’s poor time  management, is to make sure that their time management problem doesn’t  become *your* problem. That’s easy to say, but it can a bit difficult to  actually achieve.
The way to avoid making other people’s poor  time management your own problem will be different depending on the  relationship you have with that person. When you’re dealing with a boss  with poor time management skills, you can’t just say “It’s your problem,  you solve it.” For example, your boss may come in with an urgent  question that he needs you to answer for him today, but you’re still  busy working on the urgent project that he assigned you last week and  that’s due tomorrow. The only way to solve this is to let your boss make  the call on what can wait. Point out what your workload is, what you  can deliver in what timeframe, and let him decide on what’s most  important. This way, you’ll make it clear that you’re willing to do your  part, but that you can’t do the impossible, so if he keeps asking the  impossible it will be his problem, not yours.
Sometimes you’ll  have to deal with poor time management of co-workers. If you know this  beforehand, make sure to agree with the person you’re both reporting to  where the boundaries of your mutual responsibilities are, and point out  where you are dependent on work by others. This is actually not  different from common project management techniques: try to figure out  beforehand where the risks are, factor in enough time to deal with the  risks, or have a plan B in place. Don’t fall into the trap of doing it  yourself when work promised by others is not delivered. Apart from  making you a very popular co-worker, this will only signal to your  co-workers and to your boss that they can get away with it, because any  problems they’re causing will be solved by you. When a project is very  important you may do this once, but do this repeatedly and you’ll burn  out very quickly.
A third situation is when you’re dealing with  poor time management in subordinates. In this case, you need to give  them just enough assistance to get them going, but not so much that  you’re doing significant portions of the work yourself. Coach them into  creating a schedule for what they committed to doing, and make sure it’s  their own schedule. Ask them if they think it’s a reasonable schedule,  and what they will do if something turns out to be more work than they  expected. If they agree to a reasonable schedule but still fail to stick  to it, let them explain why. If there was an emergency, could they have  foreseen it, or factor in additional time to compensate? This way, you  keep them accountable for what they committed to, instead of making  their time management problem your own problem.
In all these  cases, it’s very important to be clear about your own commitments. If  you promise to deliver, make sure you deliver. You have to make sure  that you take your own commitments seriously, because that’s the only  way you can expect the people around you to do the same for their own  commitments. Also make sure to remind people about their commitments. If  a co-worker promised to deliver a report by Monday morning, remind him  by noon if it’s not there. If you wait till Tuesday you’ll give the  impression that it could have waited anyway, so next time he will not  take your deadlines seriously. If for some reason it’s not possible to  set a crisp deadline, you still want to remind them periodically about  it. Putting a task for this in SuperFocus, for example “Remind J about  policy document?” has proved very effective for me. When this task  stands out, it means it’s bugging me enough to start bugging J about it.  If it doesn’t stand out, apparently it’s not important enough yet to  bother with it. This way, my own time management system helps me clarify  my own priorities to the people I work with.
Usually you don’t  need to evangelize about your time management system to your co-workers.  People will notice that you’re reliable to work with, and they will  want to work with you. As a result, you can be picky about who you agree  to work with and of course you’ll choose to work only with the reliable  ones. In the last job where I had a direct boss, it took him only a few  months and one project with an unreliable co-worker to realise that I  would be far more effective working with the people I chose to work with  instead of the people he assigned me to work with. Problem solved!