It helps me to separate the inbox of my todos and the 3 top tasks I hope to achieve during the day. My notebooks and Todo apps are the inbox that I will add tasks to throughout the day. But I usually try to finish my top 3 in the morning. They are usually things I do for own growth, such as learning languages, reading, and writing. So even there are new and urgent tasks later that day that I need to respond to, such as responding to emails, at least I've accomplished something for my long-term goal. It also helps when you communicate with your colleagues, friends and family to plan ahead your time together, so there are less unpredictable tasks.
I write an extensive list in the evening as it comes to mind. Prioritize by numbers. The next morning I will revise the list and do three most important tasks until they are done.