How do you keep each individual task relevant and clear? Break tasks down into the smallest reasonable units. Big tasks take a long tim...
Big tasks take a long time. Say you have this one large task - say, "plan the vacation" - on your list. You'll probably look at it and think "Nuts. That's too hard to do now. I'll wait till I have more time." And no matter what priority you set for it - assuming you use priorities - your natural tendency will be to put it off.
The solution is simple: break down the task into smaller, more manageable subtasks. Each subtask will be easier to think about, and take less time to complete. Now, you will probably find you can squeak out one or two subtasks more often because it's easier to find the time to do something that doesn't take long and the solution to which is relatively straightforward. This is just an example of one of the most basic problem-solving techniques: divide and conquer. It works in politics, war, programming, science, management, and so on. It's even been used for parables.
If you accept that divide and conquer is a good method to use, there are two immediate sub-problems that follow. (You might notice that we are using divide and conquer here to explain divide and conquer!)
How do you break down a complex task?
How finely should tasks be broken down?