Currently, I'm exploring this topic because I'm making my own productivity system. I'm using a combination of notion, google calendar, and good old sticky notes hah. I'm building the routine of planning my day the night before. Most of the habits I'm developing are written down on sticky notes in my room so that I'm reminded that I have to do them every day. I use google calendar for work, faculty, events, training... And I use todoist to capture my taught which I put into notion when I get the time and track them with an urgency/importance matrix.
How do you stay productive? Would help a lot since I'm at the beginning of my productivity journey.