Personal experience, obviously:

1. enforce time limits on apps (like 45 min messaging/social per day), e.g. using built-in tools => frees a lot of time
2. streamline communication, i.e., do not be available 24/7 for mail, chat, etc. Instead, define time windows to check and answer your channels
3. Use some Pomodore timer [1] to focus on specific tasks for a few hours. Minimize distractions as far as possible in that time window.
4. Sleep. Working tired is a black hole for time management.
5. Do sports/seek nature to keep the stress level down.
6. Plan honest to your capabilities, sometimes the 80% solution will do (yes, this can be hard to accept)
7. A simple hand-written checkboxed ToDo list per day is helpful, take 5-10 minutes to compile it before your day starts.

[1] Goodtime

Look at the stars for a while.