Most of them focus on outward activities—doing things such as forcing yourself to write. Set a timer and stay at your computer until you write 300 words. Get an accountability partner to whom you have to confess if you don't meet your goals.
Do they work? Probably. But they don't solve the problem. Lack of motivation is an inside job. You can circumvent the trouble by performing or doing things, but you don't diffuse the problem. It will recur.
I can force myself to write or
I can look inward for solutions.