you're going to get a lot of different answers on how to build your credit because you didn't give enough information on where you stand. Someone with poor credit will approach this differently from someone with no credit. I will speak on a position of no credit.
Getting a credit card and adding a small charge to it like Netflix and paying it off every month will help build your credit score but it will not do much for your credit history. I remember when I was going to purchase a car and I have a 750 credit score but was denied a loan because I had a weak credit history. At that juncture I went to a credit union and took out $1,000 cash loan put it back in the bank and pay it off using the cash over the course of 6 months. I kept doing this until I was able to borrow $15,000 which allow me to purchase the car. As Sean Ackerman said piggybacking off of someone who has a good credit history and credit scores and make large purchases would be a great way to kill two birds with one stone what if you're going to do this by yourself. while building your credit always keep in mind never spend money that you don't have although building your credit is the practice of spending money that don't have.