Self- discipline is a matter of doing the things you need to do – when you don’t feel like doing them. And doing them to the point that you actually start feeling like it more often.
The secret of the most disciplined people you know is not that they are good at self-torture: if you do anything enough it starts to feel normal. Force the habit of anything for awhile, and it’s hard to do anything different.
Habits aren’t developed overnight. The decision however, can be made at any time.