I've always looked with disdain and smugness towards the self-help category in libraries. As far as I'm concerned these books are false promises at best, and esotericism at worst. You'll commonly see covers with unrealistic statements: "Get fit in 5 minutes!", "Learn the guitar in 2 steps!", "Master cooking while asleep!", and so on.
However, I'm also a person who struggles mightily to get focused and not get sidetracked of life by funny cat pictures. So, for years I’ve been doing a conscious effort to track what I'm doing and how I work.
At first, I thought it was only about the willingness and I tried every methodology I could get my hands on (GTD, Pomodoro, etc), and then blamed them when they didn't work. My eventual gotcha was understanding that nothing would work as long as it kept requiring our precious and extremely limited resource: Willpower.
This happened when I came up across a concept in Scott Adam's blog about the value of focusing on systems instead of goals; You don't become a good writer by setting a goal to have a best seller. You become a good writer defining how often you practice writing, read other authors, receiving feedback, etc.
There are two books that I strongly recommend on the topic:
By Scott Adams. Before becoming batshit crazy defending Trump, denying Global Warming and just being a contrarian for the kicks of it; Adams wrote this book that focuses on his professional career and his long list of failures.
The main point of the book is to focus on goals vs systems, but it also resonated with me when Adams gave so much importance to the factor of luck. There are so many tales out there, with clear survivor bias, that tell you how someone had success just because of hard work, that it was refreshing to read his take on it.
By James Clear. James had already written about the subject and did it again in the book. But what helped me the most was his advice on how to actually work on defining those systems.
He doesn't have a one-size-fits-all solution because it simply does not exist. He instead talks about several different strategies that may fit you. One that I did before —poorly—, was a habit tracker, in the spirit of the one you find in Github or the famous advice of Jerry Seinfeld; Marking your records on a calendar and not breaking a chain.
James got me to do it again, and this time it has stuck around.