You can't manage time, it just is. So "time management" is a mislabeled problem, which has little chance of being an effective approach. What you really manage is your activity during time, and defining outcomes and physical actions required is the core process required to manage what you do.
In order to know for what purposes you spend most of your time, you can use the easy-to-install Java program: xTime. You can simply add new projects, start it, when you start to work on it, you can see how much time you have spent altogether on your project.
On Windows systems it simply hides itself in the System Tray, so it won't disturbe you in your usual work.
You don't work on projects? No problem. You also can find out, how much time you spend on ...
You tell the quest, we measure the time!
xTime is running. The asterix before the project shows on wich project you are working on.
You can add easily a new project.
It hides itself in the System Tray.