The way to build credit is to show responsibility with it. You will have to use it some to show that. I worked in finance for years. I've seen someone with a 710 need a cosigner on a car because despite the score, he had no history. One account, never used it. The bank asked for more.
Get a card, either pay it off in full every month or never go over 30% of your limit and with time, it will build your credit quite well.