Its important to be yourself, show diversity as opposed to being a broken record about a single subject, current events can spark a good conversation even if both parties are not in complete agreement, you can talk about family, work, school, hobbies, books you've read, movies, food, travel, etc. And prepare to asks your date some question to show interest in them as a person. If something seems off, don't be afraid to dig a little deeper-the more you learn about the person the better-this will help you decide if tis is a relationship worth investing in. As the friendship/relationship develops you want to make sure the person has the character traits that you value and a temperament that is compatible with yours.
If you are looking for a serious relationship I recommend that you make a list of character traits that are important to you and that you consider them carefully. If you are just dating around and want to keep it light and casual make that well known also-do whatever you can to be open and honest and expect the same from the other person.
Good Luck & Have Fun!!