Paul Graham wrote an insightful essay about doing great work that I really enjoyed. He gives advice about finding what you’re interested in to doing the actual work.
How do you find the right work? Just start working and try things out. It’s an obvious statement, which I think Graham also recognizes. He prefaces his essay with: “The following recipe assumes you're very ambitious”. With any motivational or productivity book, being ambitious is table stakes— reading the advice is not taking the advice.
I’ve worked 7+ years on an app I‘m passionate about, so I know first hand that passion alone will not get one through each day. Those are the sucky mornings you just need to punch through.
Graham recognizes this friction too, and I found this tip particularly helpful:
It's usually a mistake to lie to yourself if you want to do great work, but this is one of the rare cases where it isn't. When I'm reluctant to start work in the morning, I often trick myself by saying "I'll just read over what I've got so far." Five minutes later I've found something that seems mistaken or incomplete, and I'm off.
Give this one a read!