Answer:
In my opinion, I would say that the quote means
That in everything that we do we must be sincere, hardworking,honest and trustworthy because from our character determines what we will be in the future.
From the quote I can also say that we ought to use our God-given talents wisely because that can pave way for our achievement.
"Better keep yourself clean and bright": For me it means that we should be faithful in all that we do and always Strive to stand out positively.
"you are the window to which you must see the world" : for me, this means that it is only you that would take you to where you want to go. Only you can make yourself successful if you have that positive "I can do it" mindset.