You have to owe money that you pay back on a regular basis to establish your credit. Credit cards, a car note, car insurance and a house note will all help to establish credit. It takes years of good credit to achieve a high credit score.
The main thing is do not miss a payment and do not spend over your ability to pay.
There is debate about canceling credit cards. I have one I do not use, they charge no fees, so I have not canceled it, because I do not know if it will harm my credit rating. The credit card companies say it will. The credit bureaus will not give you an answer. So if you do not plan on using a credit card, do not take it, unless there is some tremendous discount on the product if you agree to sign up for the card. In that case after you get the product and pay for it, put the card away or cut it in half.