I don't think trying to "motivate oneself" will bear a lot of fruit. Motivation is a combination of beliefs: belief that a thing will be beneficial, and that it's possible.

That's at the macro level. On the micro level, structure helps a lot. Some of the more go-getter people you know are just on autopilot, but have done the work beforehand to hack their motivation, mostly by forming habits and setting themselves in social environs that reward achievement.

Motivation is a fickle, mercurial beast. Trying to run on it at all times won't work. Use motivation wisely, for short bursts of work that get/keep autopilot-you on track. Things like: going to sleep when you want to stay up, making a plan for issues you don't want to think about, setting habits to do things you don't like to do.