In today's multitasking world project managers are often running three or more projects. These may be small in nature but like a juggler with many balls in the air you need to keep an eye on them all. You cannot focus on one or two to the exclusion of the others.
How do you do it?
The Orientate part of the OODA loop (Observe Orientate Decide Act) has to have constant feedback from the Observe part of the loop. You have to be regularly reviewing each of your projects to ensure nothing gets missed. This particularly important when a more pressing task is superimposed on your regular workload. The tendency is to focus intently on the urgent, the immediate, at the expense of the overall picture.
One method to counteract this tendency to over focus on the immediate is to mind map all your projects every week. (http://en.wikipedia.org/wiki/Mind_map ) Create and re-create all your projects on one big mind map. The very task of drawing all your projects and their tasks - high level - will act as an antidote to project myopia: A condition we all can suffer from, particularly when under pressure from our leaders.
It's a sad fact of life that when a juggler drops a ball we don't marvel at the four still in motion, we focus on the one sitting motionless on the floor. Mind mapping won't make managing your projects any easier, but it will give you an early indication if you're about to drop the ball. Then you can Orientate to that problem and decide what to do. Even it's only to tell your boss that a ball is about to drop. A juggler who passes out the ball to his assistant before it drops is considered skillful, so is a project manager!