A couple of ideas I came across, online and from a colleague recently, to start and finish the day.
Creatives often start early, and spend the first 30 minutes of the day writing, often before breakfast. This is a great way to have a positive effect on the day, for momentum and creativity.
And an excellent suggestion for the end of the working days is to spend 5 minutes jotting down what you have learned, and taking time to thank those you have help you or who you have been able to learn from.