My main way of staying organized is my planner, which is loosely a bullet journal, but basically it's a hand drawn planner and I have specific short-hand designation for events, appointments, tasks, notes, and completed tasks and moved tasks. Which helps me to stay organized on a day-to-day basis. I could take a picture of it later, but there are also lots of examples online :). I do 1 week for each two page spread, and I have a section for each day, and then a large notes section for random stuff.
I also have a dry-erase calendar which I keep track of appointments and events on for the entire month, a dry erase board which I mostly keep a shopping list on, but also anything I need to remember, and I always have a document open on my computer with things I need to do/remember, but don't need to do RIGHT NOW.
So basically I use the dry-erase calendar and the document to plan out my week in my planner :).
And if all else fails and I absolutely cannot forget something, I tell like 10 people to please remind me and send me a text so I remember.