From Wikipedia: ” Procrastination is the practice of carrying out less urgent tasks in preference to more urgent ones, or doing more pleasurable things in place of less pleasurable ones, and thus putting off impending tasks to a later time, sometimes to the “last minute” before a deadline.”
In simple english it is wasting time when we know we should be doing something useful. I think it works a bit differently for Designers. Normally we are very active and we do what we know needs done. But sometimes, i think we dont feel ready..sometimes we know there is something missing from all the knowledge that we have, we just cant put a finger on it. So we let our subconscious mind sort it out.. We get busy with something else, while in you mind you are working for a break through.
It is important to realise that this is an important part of the creative process and not let this worry you. For too many of us this leads us to working in the last minute. It doesnt mean that we get the answer..it just means that at that stage we compromise to work with what we have. and we stop looking for that missing piece.
Now once you understand this, any designer can get over procrastination by turning it the other way. Break the task in stages..some are very clear to you from beginning..go ahead and do them first..keep it aside and keep working at it like a jigsaw puzzle. I call this the movie making way of doing projects. When movies are made..you dont shoot them in sequence..you shoot them in a order that works best for budgets, people and resource.
I have done many complex projects like this and i must say it gives you a thrill when you see the puzzle falling in.