The reality is that if you are in your 60's your credit score had better be in the 800's or it means you are not very financially responsible. I absolutely trashed my FICO in my 20's and had to file bankruptcy. Tough pill to swallow. After that I just simply made sure I was never late on any type of payment I had and the rest took care of itself. As you get older and continue to be responsible and not bury yourself in debt the credit score grows on it's own.
Pretty simple concept. Pay your bills. Don't buy things you can not afford.