I hate to quote Nike here but I honestly "just do it". It starts by doing something that I have to do, no matter what it's gotta get done. While I'm up, I figure, "Well, I'm already up, I guess." Then I do something that doesn't need to happen but could use some doing. If I do this after every time I get what I need done, eventually I get some motivation.
To get the creative juices flowing? Well, to do that I make myself go out and get the morning paper for my grand dad in-law. When I'm out there, the sunrise inspired me to take a photo of something, which I do. After taking that photo, I can sometimes get motivated enough to work on poetry or this book I'm writing. Takes some doing but it's worked for me.