1. If you’re not responsible with money, don’t get a credit card.
2. If you’re responsible with money, get a credit card with good rewards. This article is a year old, but it’s a good primer on picking one: The best credit cards for 2016.
3. Never carry a balance on your credit card. Use it, and pay it off immediately. If you can’t afford something without the credit card, then don’t buy it (see #1).
That said, if you’ve already gone into debt, start here.