“Time realists look at a task and break down the math of it. They’re conscious of how long things take, and they factor that in to their plans for the day. Time optimists, by comparison, are just that: hopeful about things they would like to do. It leads to them to overstuff their days and become frustrated when their list of to-dos doesn’t get completed.”
In order to master time management, you first need to learn how to realistically assess the time it takes you to do various tasks.
The New York Times explains how to become a time realist and suggests you use no more than four communication platforms, integrate your to do list into your calendar, and categorize activities based on the level of concentration they require.