One of the points that Chris Reynolds makes in our course on High Performance Productivity is the idea that "Your environment is stronger than your willpower." This is, of course, simply a variant on the ubiquitous "You're are the average of the five people you are closest to." If you are working in a messy environment, it's hard to turn out clean and pleasant work. If you're working in a pleasant and friendly environment, you're automatically predisposed to perform better. Obviously we can't always control every single aspect of our environments, but those elements we can control, we should, and should do so intentionally.
Your own personal workspace is the easiest place to start. Is it clean or is it cluttered? Are you going to make the argument that you can only work if it's cluttered? Or are you willing to clean up the space and put systems in place to keep it clean? What sort of distractions -- visual or audio -- are there? Can they be eliminated? Why or why not?
What about human distractions? Are there visitors to your office? If you're in a co-working space or open office plan, are you in a position in which you can be easily approached? As for the people around you, what are they like? Are they people who can help you be more productive or people likely to ask you to take far more coffee breaks than you should take?
We all have different personalities and ways of working and not everyone needs a quiet, clean, aesthetically pleasing work space in order to deliver their best work. Just the overwhelming majority of people! All joking aside, use your personal self-awareness to create your ideal workspace. There should be nothing stopping you from taking this basic step.
If your workspace is your external preparation for high performance productivity, then your schedule is your internal preparation. A clean, well-lit, quiet workspace can't live without a well-planned schedule for work and for the day. How is your day arranged? Is it consistent? Does it follow a plan that you impose, or is it the haphazard reactions of someone reactive rather than proactive?
When married with a to-do list, a schedule is an infallible measure for your productivity on a daily, weekly, and monthly basis. It allows you to make adjustments based on daily feedback. If you find yourself exhausted, you probably over scheduled. If you had some periods of slack time, you might have been under-ambitious in your plans. A proper schedule and curated workspace, matched to your way of working and personality type, is unstoppable in the world of productivity.
The eight hour work day is only one of a set of lies that we buy into as a society. Another is that "being productive" means "doing a lot of work." This is not true. Being productive is nothing other than doing what you need to do well. This doesn't mean being uselessly "busy" to look like you're performing, but rather being focused (and often calm) as you do fewer things well, rather than many things at an average, or worse, bad level.
Ultimately, productivity is something that leads to more workplace and life satisfaction. We've all experienced that joy when it comes to accomplishing a good day's work or completing items on a to-do list. Productivity doesn't happen accidentally, but through intentionality combined with perseverance. Intentionality doesn't mean that you will necessarily hit peak productivity every day, but perseverance means you won't have to, because you'll continue to perform even when you don't feel at your best, and you'll continue to perform even when you've "failed" the day before.