Be careful when you use "自強不息" though. I have never seen any native speaker who is also a sane person use it in daily life without sounding sarcastic.
This word does mean what you say, but it probably one of the overused, insincere, and meaningless words in government speeches.
It's like people roll their eyes when tech giants says "make the world a better place" for the past 30 years. But instead of 30 years, this came from 《易经》,which was roughly from 5,000 year ago, and has been constantly used in a similar fashion since then. So imagine how a Chinese speaker will think of it.
自強不息, or “Pushing forward to better yourself without ceasing,” I think? Maybe there’s a better way to put it?
Another poster mentioned 点滴穿石 which is my second favorite. It puts things in perspective quite well.