How to spend time effectively?

If this is a time management problem, then the first step is to establish what you need to do, how important each task is & the time needed to do it.
This can be as simple as just writing out a to do list.
This also works, however you have too much time & do not wish to waste it.
The important thing is that it enables you to focus, find & set goals.
Of course there is the satisfaction of seeing progress as you finish each job with a tick!

Hope this is of some help