Sometimes it can be hard to get going on your productivity. I am not one to force motivation. I like to build it. If I need to get going on projects and tasks, it may be easier to start with smaller tasks which are less urgent. Some may call this a form of procrastination. I think of it as keeping in continual motion. Trying to muscle your way to motivation is often a losing cause. You will spend wasted time just trying to get going on anything meaningful otherwise.
To get the creative and work juices going, sometimes the best thing to do is clean your office or make phone calls you need to catch up on. These are easier tasks that get you moving and building momentum. I find it helps me to get things done while my motivation starts to shift from reluctance to eagerness.
If you find yourself stuck in first gear, the best thing may be to clear your smaller tasks to get to the bigger tasks.
As a tip, I like to keep these in a smaller list like Google Tasks. Keep that list going and use it for times when motivation is low to build momentum.