1. Don't force it. You can spend time grinding through something, and it's never going to be as good as if you do when you hit it fresh. You need to rest and take time away from things, then the time you spend working on it will be more productive.
2. You have to take care of yourself. Regulating your caffeine, alcohol, sugar, etc. intake is important. You don't have to hit the gym 2 hours a day, but taking a short walk or something else, really helps. If you are always tired/sick you are never going to be at your best, and you'll eventually waste more time than you are actually being productive.
3. Understand what motivates you. You can't get into something for the wrong reasons. I program, because I like programming. If you start something, because it's a means to an end (like I want to program, so I can make a lot of money), ultimately, you aren't going to do well.
I'd recommend that you make the time to hit the gym at least three times a week and lift (it really only takes 45 minutes per session). The goal is not to get ripped; it's to get healthy and balanced. Beyond the physical improvements, it makes a huge difference in confidence, motivation, and concentration. We're still physical beings after all.
I know for myself it really changed how I felt when I made the move to barbell training. Heavy compound lifts require a sort of zen-like focus that really clears my mind and re-centers me. I can't tell you the number of times I've walked out of the gym with my mood having done a complete 180 from when I walked in.
2. You have to take care of yourself. Regulating your caffeine, alcohol, sugar, etc. intake is important. You don't have to hit the gym 2 hours a day, but taking a short walk or something else, really helps. If you are always tired/sick you are never going to be at your best, and you'll eventually waste more time than you are actually being productive.
3. Understand what motivates you. You can't get into something for the wrong reasons. I program, because I like programming. If you start something, because it's a means to an end (like I want to program, so I can make a lot of money), ultimately, you aren't going to do well.