Start your day with this question: What is the most important thing I need to do today? Whatever the answer is, do that first! Waiting and putting things off creates negative emotions such as fear and avoidance as the day creeps on.
People spend a lot of time talking about "priorities", but after reading Greg McKeown's book "Essentialism: The Disciplined Pursuit of Less", I've learned that "priorities" is a relatively new word in the English dictionary. Until the 20th century, it was PRIORITY. Only in the last century have we pluralized it. In a fast world, we feel the need to pluralize the things that are important, but we are still bound to the same truth: we can only actually focus on one thing at a time!
There's a difference between your priority and prioritizing. Prioritizing puts things in their proper order of importance. This is good to do. When making a list of things to accomplish, prioritize the list. Guess what, the item at the top is your priority. Do that first. Once it's done, the remainder of your tasks will flow much smoother.