Hard work.
Or marry someone rich, and maybe get rid of them if necessary.
That is easy to say but in reality sometimes you cannot just marry a rich person just to make you rich, you must have a look of a superstar to let someone marry you. Rich do protect their money so they will not just marry anyone who will just take their money in the end.
Haha I think that is a good idea that you are going to marry someone rich. And you are lucky enough if you are able to be married with a rich wife/husband.
I don't know if his/her family is going to accept you that way easily. So, good luck!
If the families knows your intention they will make it hard for you to marry their child and that is also dangerous even if the one you want to marry is deeply in love with you because the family will make a way to even kill you to protect their riches.