If you want the confidence that comes from achieving what you set out to do each day, then it’s important to understand how long things are going to take
Overoptimism about what can be achieved within a certain time frame is a problem
So work on it
Make a practice of estimating the amount of time needed alongside items on your ‘things to do’ list, and learn by experience when tasks take a greater or lesser time than expected
Give attention also to fitting the task to the available time
There are some tasks that you can only set about if you have a significant amount of time available
There is no point in trying to gear up for such a task when you only have a short period available
So schedule the time you need for the longer tasks and put the short tasks into the spare moments in between