Get a couple and an Amex, that should start to build your credit nicely.
Credit is a PITA no one wants to give it to you until you have it, its a catch 22. Actualy
AFAIK car loan seems to be the most reliable way to build credit so you can say buy a house. Also have a bit of money in the bank helps to because they look at savings and income.
Get in the habit of pulling your credit report at least once a year just to keep and eye on things.