Ways to work on self improvement?

Anybody have any tips for strengthening your concentration, work ethic, and self-esteem? I feel like these are my three biggest problems. When it comes to something like the body it is easy. Need to be healthier? Exercise and eat smarter. Or if you need to learn a skill just practice it. But how do you work on any of those three? Try concentrating harder? If I could concentrate on things I wouldn't have to work at it. Try working harder? Same thing. I can maybe force myself to work harder some days, but I feel no sense of importance or accomplishment from it and it doesn't form a habit of working harder. Then with self-esteem I can't just not hate myself or feel more confident. If I could easily just change my way of thinking then these things wouldn't be a problem. So basically is there any sort of long term training I can do like I would to strengthen my body or learn a skill, but for those three issues? Or should I just see a doctor and get medicated?