"Hard work" isn't just manual labor. It means using your brains as well to get ahead.
I've met many successful people, and they all have one thing in common. They work hard (and apply themselves well, same thing but it takes out the stupid toilet cleaner comparison).
As for success, what is it? Not just being rich, that's an immature fantasy. Money makes things better but it does not solve all problems, nor does it bring happiness in and of itself. I've met many wealthy people, self-made wealthy people, who were not successful. For example, many of them worked 80 hour weeks, sacrificing friends and family, and despite their wealth were bitter and unhappy.
Success is not a destination but a never-ending journey. It is placing goals ahead of you, reaching those goals, and then moving onwards to bigger and better goals, reaching those and moving still further on. It is consistent and constant self-improvement which (many of you will find and some of you I'm sure know already) is the only environment that allows us humans to be truly happy.
To define it better: stagnation is to success as poor is to rich.
Perhaps the best success catch phrase I can think of right now is "Don't work harder, work smarter." Or Heinlein's definition of happiness, "Happiness is working long, hard hours at something you really love doing for the benefit of people you really love."
Luck? never heard of it, good or bad.
University degree? folks, my job is to take loan applications from people all day long. Of the many questions I ask, income and education are included. My findings after many years of doing this? If you want to be affluent middle class, get the best degree you can. It provides certification and opens doors. If you want to be truly wealthy, self-made wealthy, don't bother.