How can I improve my credit score?

I’m in the process of trying to rebuild my credit (just bad spending habits when I hit 18), and I’ve repaid everything I owed…now I just need to get some GOOD credit on my rather limited credit history.

I know about paying bills on time and taking out a secured credit card, but this morning my mom suggested taking out a secured loan, too, and paying it back over a year. So I was wondering if I was missing any other little things I could be doing to build up good credit.