At some point in the day, people have a choice of what work they are going to do next. By default, most will do what is most enjoyable or easiest. But you don't want to be most people.
As you look at your list of work that you want to accomplish today, choose the hardest thing first. The hardest work matters most. The hardest work will create the biggest impact. By doing the hard work that most others avoid, you become more valuable.
Solutions for easy problems come easily because we know the saying if it were easy, then everybody would be doing it. A likely counterpart is knowing that what is hard won't be done by everybody. Good thing you aren't everybody. Do the hard work.