Since I mentioned toothpaste earlier, I'll stick with the theme. Do you think about brushing your teeth? Is it something you dwell upon and dread at least two times per day? No. Of course not. This certainly wasn't the case when you were a child and you went kicking and screaming to the sink, but it's no big deal now because it's become a consistent habit. And guess what: It makes you feel good! Without a doubt, the biggest way to create success is to create consistency by making small behavioral changes. Consistency and willpower may as well be a muscle group. The more you use them, the stronger they become.
It's also important to note that success is built on small, sustainable changes. How many athletes do you know who go straight to extremes like, "I'm going to cut ALL sugar out of my diet forever," "I'm going to run every day for a year," or "I'm going to become totally paleo and gluten-free." Truth is, these conditions are hardly sustainable and very difficult to maintain on a consistent basis. While I don't discount the health benefits to all of the above, I recommend small changes at first. When those become second nature, add in new challenges.