Motivation can wane and is too dependent on mood and circumstance for my liking, it's fickle. Sometimes it's extremely hard to get motivated and focus, how many times have you found yourself thinking 'yes I know why I ought to be working, my dreams, family, goals etc but today I just don't feel like it...I need a break...'. Don't get me wrong motivation is excellent when you have it but it's not always there when you need it.
Habit though, habit is what will really determine where you are in 12 months time. If you build good habits, things that you HAVE to do every day that become part of your autopilot program, you'll be more productive than you've ever imagined and with very little effort (after the initial period). The reason being that things you do without thinking, require little mental effort, your brain doesn't get chance to argue with itself anymore, you just get things done, just like driving a car.
Research suggests that it takes around 21 days to fully develop a habit and I've always found the first week to be the worst. As a practical example before lunch time, I have to create 1 new PBN site, every morning without fail and it's now a habit. I used to hate creating them, the content creation, initial setup etc was such a chore for me. By the end of the week now though, I have minimum of 7, that's 28 a month and huge ranking power. Once that's done, that's a productive day for me, I feel great, anything else on top is a bonus. You start feeling like a person that gets things done which has a knock on effect to everything you do or set your mind to.