Motivate yourself to work hard
The "hard" part for me is choosing and accepting what it is that I have to do (otherwise known as procrastination, or finding my passion). Once I've made the choice to do something, I try not to think so much about how difficult or frustrating or impossible that might be; I just think about how good it must feel to be that, or how proud I might be to have done that. Make hard look easy. I like that challenge. I like being the kind of person who is capable of that.
Every kind of work has bits that are difficult or challenging or things that might not be so easy to do; try to keep in mind that the icky part is necessary to the whole. If it's not necessary, then you shouldn't do it; and if you can change it or manage and fix it to be less difficult, it stops being so "hard" and instead is just "done". Break your hard work into component parts; it makes it easier to see where the obstacles are so you can be prepared to overcome them.
If I fail because I lack time or talent or luck or if fate intervenes to keep me from being able to achieve a goal in quite the way I'd hoped, that doesn't mean I'm a failure. But if I fail because I didn't work hard enough, I'm either a half-assed quitter or lazy or stupid, none of which are what I want to be. I can only blame myself; I can't even claim I was beat or not good enough because I didn't try! I hate blaming myself. I'd much rather blame everybody or everything else; I'd guess we all would.
Being able to take on a challenge and persevere and sometimes succeed; being able to transform myself from newbie to capable and experienced; and being able to find or happiness in doing work that's satisfying is a well-earned, hard-won reward in itself. I want to be fully immersed, challenged, feeling really good about my effort all the time. I want to be hard-working; that's how I motivate myself to work hard.
Take a lesson from our friends in the Last Mile program at San Quentin: "How You Spend Your Time Becomes Who You Are."