The number one key to time management: write things down.
You cannot possibly just hold what you need or want to accomplish in your head and manage it properly.
Personally, I write to-do lists... a lot of them.
I have in the notes on my phone a "Primary", "Secondary", and "Tertiary" list of things to do, in the respective priority of getting them done.
Points might work their way up as the time scale makes it more and more of a priority, but it is never-ending - I just keep adding to them whenever something I need to do pops into my head.
I do the same for my content, I use a list for each platform and work my way through. Any ideas that pop into my head... straight on the list before I forget.
I also have a "To-get" list of things I need...
I know this all sounds very simple but there's real power to it.