In many cases, by far the biggest help is to have a routine and a schedule. Sometimes people can get overwhelmed by everything they have to do, so they get paralyzed into doing nothing. But if you organize and prioritized, even though you can't do everything at once, doing one little thing at a time is better than doing nothing.
I got this free Google Tasks app for my Android Phone, and it helps a lot. And if it's possible to set a time schedule and keep to it, that helps tremendously for productivity. IMO, it's the key. There are many people who aren't so much slothful as just paralyzed by lack of organization. I know a few people like that ... generally hard workers ... but a mess due to lack of any kind of systematic organization.
Guy in the OP, IMO, is dead wrong with the "I sleep until I wake up". Uhm, if you actually get to bed at a fixed time, then you get up at a fixed time. With this random sleeping schedule, your productivity overall will be severely impacted. Not to mention that if your body doesn't get used to a fixed sleep schedule, then you don't sleep as well.
Seminary Life, the way it was organized and structured, taught me this, and people in the military learn it also. There's nothing like a SCHEDULE along with organization of tasks by priority.