Productivity Hacks?

I wonder what other people are using to manage their time better and be productive.

I use google calendar and calendar.help for scheduling bigger chunks of my time, like scheduling meetings, writing sessions, etc..

I use pomotodo for smaller bite-sized tasks, like write one paragraph of the introduction section, read a paper, implement a function. etc.

That's about it. What are you using? What are some of your hacks and tips?