Let's face it, writing non-stop for a whole day requires high levels of concentration, purpose of mind I admit to not possessing!
So I try to mix a lot of different skills and interests in a work day, starting with the creative part first. I'm a morning person, so I try to write early, be it new pages to the novel I'm working on (currently Sentient) or new blogs. I think Hemmingway got it right when he said "write drunk, edit sober!" I wear two hats in a day: creative and colourful for imagining and writing; plain and conservative for the process of editing and reviewing.
Editing is a methodical process, so always be on the lookout for common pitfalls, such as getting too close to your work. When that happens, you can easily waste time by not editing efficiently, invariably leading to re-editing the work a second time. I try to edit small, manageable sections over short periods of time, usually no more than an hour. Be happy with that, then reward yourself!
Watch a movie or TV series, read a book or even better, have a night out! I attended a book launch from A C Grayling, where he eloquently presented difficult concepts in an entertaining way. I left with a new found motivation to write and communicate my own take on the times we live in.
All this makes for a productive as well as interesting day!