If you're having issues juggling large projects, take a moment to evaluate your own personal processes, it may just pay off.
In my early years as a project manager, my processes were crap. There's really no other word for it. I relied heavily on being able to keep everything in my head. This worked surprising well for a surprisingly long period of time. Now to be clear, I do not have anywhere near a photographic memory. I'd say my memory in general is a B-... just above average.
There was a finite point where my preferred method of project management came crumbling down. I was working on a project where I had to coordinate teams across the globe, with relatively short timelines. This lead to each day having dozens of separate tasks and people I needed to follow up with, each with their own thread and story arc. The sheer quantity of items to follow up on was easily beyond my capacity, it was as easy as that.
A year or so before, a good friend and fellow PM introduced me to Getting Things Done (GTD). GTD is a methodology book written by David Allen in 2001. The short short version is that it's a way to easily organize all of your work and tasks and hopes and dreams into actionable lists. I didn't put too much stock in GTD when I first read the book, mainly because I hadn't hit that apex of personal inadequacy. Once I did drive over the cliff, I got it. I get it. I understand now. After rediscovering GTD, I turned my PMing around within weeks, and saved myself and few ulcers.
My projects were in better shape and my credibility was higher, but that's not the big takeaway. The big takeaway is that if you get your personal management, your personal task and priority management in order, the project management becomes infinitely easier. If you're having issues juggling large projects, take a moment to evaluate your own personal processes, it may just pay off.